Lately I am feeling really depressed and negative all the time. I give up easily on nearly all of my work. At school I feel like a ghost. I do have friends but something's not right and have to struggle with a friend who tries to fit in, bratty and jealous.

Well maybe you just need to do what feels right to you. If you notice a change in your mood maybe that's what was causing you to be depressed.

I'd say do what you KNOW makes you happy, but if you don't see any change, try to find the root of your sadness.

Hope this helped.

I know how hard this can be. It can be insufferable.
1 tell someone, your parents, someone who loves you.
2 make sure you are getting enough vitamins and minerals, especially vitamin D.
3 make sure you are getting enough sleep.
If nothing works and it continues, get meical help. There is no shame in depression, it isn't something you can control.

Did something happen? If you're just being melancholic, that doesn't mean much, it could just be a phase.
Try to do something, setting personal records, improving your skills or find a new hobby. Also, talk to a friend of yours about your situation, alas they can help you more than most of us.