And it's okay to be sad, and if you want to feel better then you can go to a therapist, I can assure you that they can help you! And also, talk to a friend or your parents about this, they can help you!
Battling depression may be very hard, but I bet you can survive it! Just as long as you know that people care for you! Your friends and family care about you!
Your not an idiot, your perfect, and beautiful just the way you are, you don't have to change for anybody, who cares if u punched a girl? Believe it or not, loads of people do that to other girls.