Marijuana for sleep

Your best bet may be to go to your doctor and tell him/her everything and enlist the help of a professional that can guide you.

Losing sleep is very difficult to contemplate.  Did you have insomnia before you began using?  One of the withdrawal effects from the THC slowly leaking out of the system is either insomnia or hypersomnia.  You seem to be having the insomnia, no fun indeed.

Have you attempted to slowly cut back on what you are smoking at night?  You may attempt to do that and though I am not a doctor, many people do well with the over the counter Melatonin that is sold in pharmacies and discount stores. 

You may see if you slowly cut back on the amount of marijuana at bed time and ease into a small dose of Melatonin, if the combination helps you sleep.  You may also attempt to download a sleep hypnosis app to use on your phone if you have a smartphone.  Using the techniques to induce natural sleep taught on an app can help you fall asleep and stay asleep better than when you use chemicals. 

I would begin with your doctor and attempt to slowly wean yourself.  Congratulations on your motivation to stop using.  I believe you will feel better overall when you no longer use it at all.