Small Biting Bugs?

I don't know what they are. They are very little, even smaller than a mosquito. They are hard and black. They are flying all the time in my room, trying to bite me and drinking my blood. I have already killed a lot, but still they are in my room. It's hard to find them in my room, but when I am sitting on table or in the bed laying down they came and try to bite. I just start feeling worse. I need a solution soon, please.

By Fidia