Simple fix.
STOP USING DRUGS.
All drugs of every sort. Caffeine, Alcohol, EVERYTHING!
Do that for about 3-5 months and you will feel GREAT!
Also... try to eat right and exercise. Take a vitamin.
For all the shit that people like to give Teo, this is really good advice for basically any of the HPPD-like posts that people put up here. Stop doing drugs. Don't smoke weed to "help". Weed is a wonderful thing, but there's no doubt that it has potential to cause anxiety, persisting hallucinations and other weirdness. You don't have to hold off of everything for as long as Teo says, but the whole "no drugs" thing is generally a pretty damn good idea until you feel better. Get some sleep, and for god's sake, don't turn back to heroin.