[[[******(((Htown)))}}}]]]. Lotsa big hugs.
I'll start at the beginning of your share, and when I get to the end, I'll stop. I'll focus on booze because I'm an alcoholic, not because your drugging is to be taken lightly. I'll share from what I know.
I highly doubt you're pretty much the only person in the school who doesn't use. Possible, but not likely. Maybe you could ask a teacher you trust.
Most people, me included, had cravings for a long time after stopping. That's normal, in my opinion. But everyone's different.
You have an edge. You know what you know.
Yes, you're right, an alcoholic has to stop drinking for the rest of his life. What I don't read in your sharing is one-day-at-a-time thinking. You don't have to stop for the rest of your life. You only have to stop for today. All I'm trying to do is go to bed tonight sober. Tomorrow, if I wake up, I'll work at staying sober tomorrow. I can't have tomorrow's dinner today, wouldn't be useful, and I can't have tomorrow's sobriety today either. I'm 50, you're 18, you're planning your whole long life, I'm planning my next 24 hours. A camel can go 24 hours without a drink. So can you. You might get hit by a bus or killed in a drive-by, so why plan a sober summer now? Today is the only day there is. You're not guaranteed tomorrow.
Your next sentences indicate you paid a pretty high price to get here. You didn't surrender easily. Don't pay any more dues. You've hurt enough.
People who are allergic to peanut butter still crave peanut butter. Diabetics still crave sweets. People with high blood pressure still crave salt. You aren't unique. Neither am I. When I see a row of liquor bottles in a bar, unwelcome thoughts sometimes still appear. I simply say, "For others, maybe OK. For me, POISON!"
Parting thought: Find the AA slogans. Write them out. Refer to them often.
I've been sober over 17 years. Remember, I'm pulling for you. We're all in this together.