Get more sleep. Stop hanging around people that bring you down. Never wear your hair like that again...
Run. Go far far away and never come back. You don't know everything, you don't have all the answers. It's okay to accept help from people who know more and have answers. While it's hard to see, so much of what you stress over won't matter when you're 40. People are the most important thing.
Don't stress so much about doing well on a particular assignment. Try to have a balance of things in life. School should be important but also spend time with friends. Try to enjoy yourself.
Eventually, find something you love to do.
Don't care so much about what people think about you... don't dress so crazy.
Don't take life too seriously, you don't need to be involved in every organization. Don't wear yourself too thin.