I'll try to contribute some thoughts for you. First for your depression, this is really something that should be helped by a professional who is trained to help people with these issues. You would do the right thing by first speaking to your own doctor who can then refer you to somebody who would be best suited to help you. Trying to manage this on your own is just inadequate in many cases.
As for the studying, my study habits video
has helped thousands of students so you should be able to take away some points from it as well. Then adopt an effective study habit to help maximize your grades.
Then as for your reference in 'everybody' who is sort of happy to see you fail, I have an entire article to help you manage how others think about you
. If they are people who truly want to see you fail, then you should not associate yourself with them in the first place. Get a better group of people to hang with.
Hope all of these will help.