How do I stop being depressed?

"Before 你 diagnose yourself with depression 或者 low self-esteem , first make sure
that 你 are not, in fact, simply surrounded 由 assholes."
- William Gibson
From what I've heard, 你 have a really unsupportive group of people surrounding you. No wonder 你 feel so low. It's definitely hard to remain happy, optimistic 或者 positive when negativity surrounds you. First try talking to your parents. Tell them politely but firmly that 你 think your brother's antics are going out of hand and to take matters into hand when his antics are starting to get nasty. Of course, a little bit of sibling fight is healthy, but as long as matters stay in hand. And for those people, who are making 你 feel bad, ignore them. They just won't be able to feel good about themselves until they hurt somebody. Sometimes if they get that their cheap mindgames are not breaking through to you, they may drop it. But if 你 find that, with every time 你 remain silent their bullying increases, speak up and give them a peice of your mind so that 你 will able to sleep well and peacefully at night.
And as a last resort, try moving out as soon as 你 can and try hanging out with a new group of friends. Hope everything works out for you. Good luck :)

Well actually I had and am facing similar depression from past 2 weeks. Yesterday I cried all 日 because of a person.

But 你 know what crying for people who really don't care about 你 is a waste of time and I have realized it. If your parents don't care about it then don't cry like a coward and just let them know that if they don't care 你 won't care about them too.

A tip as your 老友记 bully 你 (they aren't actually your 老友记 then but your enemy) ignore them, be 更多 confident and read inspiring books, engage your self in 音乐 (it will give 你 relieve) and instead of listening sad songs and cry try to listen pop songs and enjoy them. 移动 out for a walk when 你 feel 你 are loosing your self and enjoy nature.

摄影 is a good way to express your feelings to the world. 你 can write a diary so that there'll be someone whom 你 can tell everything.

Paper is 更多 patient than people and they won't share your secrets 或者 make fun of you. Plus 写作 diary in English will improve your 写作 and speaking skills. 你 can always use a dictionary.
Don't hurt (physically) your brother back as maybe it could make the situation worse. Because he could attack 更多 violently.

And feel free to talk to me anytime 你 want. I will listen to you. Because I feel strangers can understand your 或者 mine problem better than our close persons.

Be Positive ^_^
Lots of hugs