' Just as a skilled physician has different medicines for different ailments, so the Buddha has different antidotes for the different hindrances, some equally applicable to all, some geared to a particular hindrance.

(N.b. The five hindrances are: 1. craving, 2. ill will, 3. dullness and drowsiness, 4. restlessness and worry/remorse, 5. doubt.)

In an important discourse the Buddha explains five techniques for expelling distracting thoughts.

1. The first is to expel the defiled thought with a wholesome thought which is its exact opposite, analogous to the way a carpenter might use a new peg to drive out an old one. For each of the five hindrances there is a specific remedy, a line of meditation designed expressly to deflate it and destroy it. This remedy can be applied intermittently, when a hindrance springs up and disrupts meditation on the primary subject; or it can be taken as a primary subject itself, used to counter a defilement repeatedly seen to be a persistent obstacle to one’s practice.

For craving a remedy of general application is the meditation on impermanence, which knocks away the underlying prop of clinging, the implicit assumption that the objects clung to are stable and durable.

For craving in the specific form of sensual lust the most potent antidote is the contemplation of the unattractive nature of the body.

Ill will meets its proper remedy in the meditation on loving-kindness (metta), which banishes all traces of hatred and anger through the methodical radiation of the altruistic wish that all beings be well and happy.

The dispelling of dullness and drowsiness calls for a special effort to arouse energy, for which several methods are suggested: the visualization of a brilliant ball of light, getting up and doing a period of brisk walking meditation, reflection on death, or simply making a firm determination to continue striving.

Restlessness and worry are most effectively countered by turning the mind to a simple object that tends to calm it down; the method usually recommended is mindfulness of breathing, attention to the in-and-out flow of the breath.

In the case of doubt the special remedy is investigation: to make inquiries, ask questions, and study the teachings until the obscure points become clear.

Whereas this first of the five methods for expelling the hindrances involves a one-to-one alignment between a hindrance and its remedy, the other four utilize general approaches.

2. The second marshals the forces of shame (hiri) and moral dread (ottappa) to abandon the unwanted thought: one reflects on the thought as vile and ignoble or considers its undesirable consequences until an inner revulsion sets in which drives the thought away.

3. The third method involves a deliberate diversion of attention. When an unwholesome thought arises and clamours to be noticed, instead of indulging it one simply shuts it out by redirecting one’s attention elsewhere, as if closing one’s eyes or looking away to avoid an unpleasant sight.

4. The fourth method uses the opposite approach. Instead of turning away from the unwanted thought, one confronts it directly as an object, scrutinizes its features, and investigates its source. When this is done the thought quiets down and eventually disappears. For an unwholesome thought is like a thief: it only creates trouble when its operation is concealed, but put under observation it becomes tame.

5. The fifth method, to be used only as a last resort, is suppression — vigorously restraining the unwholesome thought with the power of the will in the way a strong man might throw a weaker man to the ground and keep him pinned there with his weight.

By applying these five methods with skill and discretion, the Buddha says, one becomes a master of all the pathways of thought. One is no longer the subject of the mind but its master. Whatever thought one wants to think, that one will think. Whatever thought one does not want to think, that one will not think. Even if unwholesome thoughts occasionally arise, one can dispel them immediately, just as quickly as a red-hot pan will turn to steam a few chance drops of water. '

- by Bhikkhu Bodhi (from, The noble eightfold path: the way to the end of suffering ) available for free at: https://www.accesstoinsight.org/lib/authors/bodhi/waytoend.html

'Herein the disciple rouses his will to overcome the evil, unwholesome states that have arisen and he makes effort, stirs up his energy, exerts his mind and strives. He does not retain any thought of craving, ill will, or harmfulness, or any other evil and unwholesome states that may have arisen; he abandons them, dispels them, destroys them, causes them to disappear.' - The Buddha

...

A lot of my problems seem to come from mental fabrications. I.e. too much thinking. 

I keep reminding myself of this when things get dark during the unpleasant process of purification. This is not an intellectual matter. I cannot think my way out of this. I still my way out of this. 

What's needed now is to stop paying attention to thoughts, to the mood, and practise single pointed attention on a meditation object instead. Not too tight a focus and not too loose, a gentle focus that can comfortably stay centred with the object of meditation without straining the mind.

At first one has to endure the taints, the greed, aversion, dullness, restlessness, scepticism (aka the five hindrances). Through it all, sit as upright and still as possible, like the Buddha under the Bodhi tree. Without judging anything that is happening, just mindful and bringing attention back to the meditation object and keeping it there, doing this over and over, calming the body, steadying the mind. 

I use different meditation objects at different times, sometimes its the breath, other times space, other times the body, the life energy (kundalini), the emotion of metta, the perception of light, warmth, cold, a primary colour, a sound, a mantra, one of the four primary elements, there's many different meditation objects, whatever meditation object feels like a good fit at the time and holds my interest. 

After a time, the composure deepens and the senses start to settle and calm down, the thoughts fade, dissolve,and the mind becomes more and more centred, more composed and unified around the meditation object, and then secluded from the five hindrances one drops into a pleasant serenity, and this connects one with a deeper part of being, a safe place below the surface level of thoughts. Like an inner refuge. 

 It involves patience at first. One has to endure the five hindrances, endure the taints, the impurities of the mind, the longing, aversion, and delusion, the crazy thoughts, let them be, and just sit as still as possible, anchoring attention with the meditation object. It can take more than one sitting sometimes before it reaches serenity. 

I did have a powerful meditation experience though which encouraged me to keep at this. Where I reached such a state of stillness and composure that afterwards the darkness was gone, and I was in a completely different mood, like I was glowing. It showed me that this is indeed the way out of the dark night. Stillness, samhadi and equanimity.