Exercise is good. And writing (and on the subject of writing, sometimes less is more, like three sentences, 'I wish he would of . . ' 'I wish I would have remembered to . . ')
And it's says that you're 21, and really this is when a lot of societal rejection and career rejection hits home. A person realizes, Jesus Christ, the world is not near as open and it could be, not near as open as it could be. And this is really a point where a person needs to be very strategic, to find ways to kind of medium-step and ping-pong careers, education, relationship, etc. Even 'neurotypical' people (and no such thing as really normal!) struggle to find accurate information about jobs. So, maybe both school and lousy jobs (and the lousy jobs, sometimes called the 'entry-level' are harder all the way around than the good jobs, they are in no way easy) teaches skills, such as learning that many so-called managers are amazingly disengaged from the job to such an extent that they don't want to hear about problems, okay, fine, play that game, strategically play that hand, and not bring up things unless they're vital. But really about 20% of the crapola jobs, a person's going to get fired no matter what they do or it's almost to the point of being intolerable where quitting seems like an absolute breath of fresh air. With increased education, as jobs become better, they are both more interesting and easier (and aspie friendlier)!
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Some medication might help with anger or aggression. I have read regarding depression that because the body's biochem is complicated and subtle, no doctor in the world can predict whether a particular patient will respond to a particular anti-depressant or not. That in a respectable way it is trial and error and it often takes about four weeks to tell if a medication is going to work or not. I don't know if it's the same here. Like in some many areas, it helps to have a doctor you can halfway talk with (a lot of doctors can't communicate worth sh*t, so about halfway talk with is about the most a person can realistically expect!)
Good luck with everything! Please keep talking here when it helps.
PS I think there may be some overlap between AS and Borderline Personality. I have read a fair number of posts where people here were at one time or another diagnosed with Borderline. And maybe the AS is correct for some people, maybe Borderline for others, and for a fair percentage of people maybe both.