I think I was raped?

So on Saturday night I went out with a couple of friends and had drinks, we v got back to their house, but at that moment I was already unconscious. Next day morning my friend told me I had sex with one of the guys and no protection was used. I don't remember this happening and even if I was aware this is someone who I would not want to have sex With. She was there and did nothing to stop this. My legs and my back are bruised and I don't know want to think of this.