Why am I in such a bad mood!?

It sounds like your going through a rough time and I feel for you I really do. With what you've described, I believe its one of the two options: your depressed or your hormones are out of wack due to having your first period and such. I suggest you try to relax by exercising, writing in a journal, think positive, AND do not continue to name bad things about yourself. Considering the scratches, this might eventually lead to something more serious so get help from a counselor, trust adult, or a parent right away. Don't go to a friend first because they might not be able to help.