Lack of self respect, self worth etc, is a common theme with us who get depressed. And it's very hard to deal with. Perhaps you could try writing a list of the things you feel you can do well, I'm sure there will be things if you really try to focus on your achievements and abilities. They don't need to be anything fantastic, like nuclear physics, just everyday things. Then try to appreciate yourself for those things. Having friends you love is a good one. They must love you too, or they wouldn't be your friends. Can you talk to any of your friends about how you feel?
Anger is another common one, also very difficult. Especially when you're young (sorry if I sound like your great auntie or something
). Don't feel bad about being angry though, it is normal. You just need to learn how to deal with it productively rather than turning it against yourself. Sometimes we feel angry about x, but really we're deeply angry about y, maybe without even realising it, and that can take a lot of time to resolve. Having said that, I can totally understand your anger at disruptive class "mates" (I had a lot of trouble with that sort of thing when I was at school). There is nothing you can do to change their behaviour, you need to find a way to stop it upsetting you so much. I guess the teachers can't control them either. Could you talk to the teacher, explain that you want to get on with learning (something else to appreciate yourself for) and ask if you can have some work you could be getting on with quietly while they are being disruptive. Then you could feel that your time is not being completely wasted and that you are achieving something.
Hope some of this is helpful.
best wishes, bel
