I am in desperate need of help?

I don't know what to do at this point. I want to be happy and I need help I am suffering from depression I think I'm bi polar but of course am not for sure because I haven't seen a doctor about it because I can't my parents don't know i find myself hiding inside my house I don't feel well enough to go out with my friends i feel like I'd be a wet blanket ruining every ones time ever since I can remember I had a very low self esteem and I just can't take it anymore I want to be happy I want to be able to function and have fun I want to feel like somebody I want to feel something other than anger sadness and fear I want to live......can someone please help me