From the sound of things, more than anything I think you just have some realizations to come to and cope with.
First, let me just throw out there, my Grandpa used to say 'if you ever have even 1 good friend in life, you're luckier than most'. Fact is, a lot of people are fairweather friends. A lot aren't - but a lot are. Unless they're in your shoes, experiencing all the things you do day in and day out, they won't understand. They can't! But that's not their fault and it's not fair to hold things like that against people. I'm not saying they're equals, but if you knew someone who had cancer and was going through chemo, do you think you could POSSIBLY understand how they felt? I'm betting no -- same concept. Also how old are these friends? Mid twenties? They probably just aren't mentally mature enough to process what you're going through in a helpful manner. How does one react to a person in your situation? What's the correct response? It's a tornado of confusion and they may feel like it's safer to step back from it rather than step into it and face the wrath. To them, it probably sounds like you've just been complaining for months on end. Even if that's not what you've been doing, can you see how it might sound that way? That gets extremely annoying. I'm not saying you're annoying, but have you ever known someone who always pissed and moaned and was never happy with anything? Always had a complaint. Always had something negative to say. That routine tires out real quick and that's not who people want to be around. But when you find REAL friends, they'll overlook that for as long as it takes and pull you up and out of that emotional grave. Right now, you have friends who will throw you some bread every now and then while you're in there, so you rot a little slower. *creepy analogy - sorry, that's how my brain works* Basically, in this aspect of your life, your friends royally suck. Got any family that's better?
Your side effects are normal. No one has FUN side effects from this stuff, but there are ways to manage them.
Your memory issues.... I'll be frank. I think your brain is fine. I think your life and it's daily happenings have emptied out much more rapidly and in larger ways than you were anticipating and now you're bored. You're bored and your mind is tunnel-visioning in on Accutane. Truthfully, it smells like paranoia. I think it's smart of you to get those tests ran, to be on the safe side but I think finding some kind of outlet is what will help you to feel better. It sounds like you're an intellect with nowhere to put that mental energy, so you've resorted to placing it all directly into analyzing Accutane, and it's making you lose your shit.
You HAVE to find some way(s) to reign this in before you self-destruct. Your school went downhill, your friends are slipping away, your hobbies and interests are collecting dust in the corner. You need some kind of buffer in your life to offset this garbage. Do you have a job? Do you have a pet? Are you in any kind of group? Something needs to give, but it probably won't just fall in your lap so it's up to you to make it happen. I feel like I can relate to you and a lot of what you're saying because I'm similar in so many of the same ways. If we are similar like I think we are, I'll tell you what I've found helps: When you set some minor goals for yourself, and work at achieving them. Why don't you go to a nursing home and visit with the lonely old people for a while. Walk dogs at the shelter. Build something. Clean your car. Just do something each day, even 1 thing, that you can be glad you got done at the end of the day. Don't let yourself plateau and let it get the best of you.
To one extent, perhaps a portion of this whole ordeal you're in is attributed to the medicine and that is just something you have to learn to cope with - preferably in a non-destructive way.
To another extent, perhaps a portion of this really is you needing to snap out of your funk and tap into some hidden inner strength.
I do care. And I do get what you're experiencing. I don't really have patience for complaining, but I do have good listening skills. If you want to talk, anytime, please don't hesitate to message me and I'll be an open ear.