Aweh man, sounds like you've had it rough over the last while. I agree with some of the other posters that it is an excellent idea to reach out to someone (whether the online professional help linked or someone you know). I am glad that you are not binge eating and that you are getting yourself to the gym! That is awesome.

That said, I can relate to the having low self-esteem and thinking of yourself as "bad", and "not worthy". Things that help me:

1) do MORE "things that make you feel like you have a purpose". like joining a club at school for something you're interested and meeting some new people, picking up a new hobby (Pakistani cooking or something :P)...

2) related to the first point, and I know this is difficult (I still struggle with it from time to time and I completely understand that it's 10000x easier said than done) but basically not reflecting on yourself so much. Not thinking "I am --- kind of person. Why did I do this today? I this I that." Instead, shifting the focus from yourself to external things as you live life. Hope this makes sense.