What do I do? Could this be seperation anxiety. or some sort of anxiety?

Think long and hard, and then think some more, and then think a bit harder before you just see if you can "get on something". Once you get on, it is almost impossible to get off and it will completely change your personality. It is OK and HEALTHY to feel feelings. It is not a disorder to be masked. If you dive into a pill bottle you will never learn how to handle this stuff maturely. The second paragraph of stuff you said is mainly signs of good habits, not bad. It means you are detail oriented which properly channeled is a great skill not a problem. What you need to do is talk this out. Don't hide in it and don't be afraid of it. All adopted kids have unresolved feelings even more so then kids born to their family. Maybe some counseling wouldn't be a bad idea, but most of what you are experiencing is just part of growing up. Its tough, and that is why you need to talk through it with somebody, but you aren't abnormal.