irritator (or w/e OP name was)- Don't listen to people saying cocaine. Personally, I crash incomparaby worse from decent street coke than I do from MA. If I were you, who apparently gets a bad amp crash, I'd veer away from all "drug" stimulants.
I'd recommend DMAE for you. It's hit and miss apparently for some people, but I've used many different stimulants, and if you're not looking for a real big "high", but a mood lift, and increased concentration, it could be for you. Not to mention, it'd be hard to argue that anything else recommended here wouldn't be worse for you haha. You either have to take it on a fairly empty stomach, or put it under your tongue if you've eaten recently. It was once scripted as an ADD med (deanol) a long time ago, but didn't go through needed testing to stay on the market. Now you can find it as a supplement. Most doses are too high, either 100mg or 350mg. You should try maby 60mg orally to start. If that works, don't use more, as tolerance would build very quick if you use the amounts that the capsules come in.
Another note, get magnesium chelate if you're using ANY real stimulants like coke or amphetamines. You'll probably be able to use way less drug, and have a smoother high, less comedown, and less body tension.
There's other shit I'd highly recommend. If you want to hear more, just PM me, I'd be glad to help you get what you're looking for, while avoiding the problems you're having with your hard drugs. There's supplements that will most likely, if used right (dose, timing w/food, timing w/stimulants, etc.) fulfill your needs without you needing to fuck yourself up

It might take a little work, but in the end it'll be way cheaper than illegal drugs and help you more long term. You can even fit them into your hard drug use if you insist, and use less drugs and have a better high and much less comedown/negative effects.