Knee Bruising/Swelling

Hello any help is greatly appreciated.

I was playing football on Sunday, I am a keeper a striker was coming in on goal and his knee banged into mine we were both running. He was fine, I wasn't straight away it hurt. Eventually I got up hobbled around and felt I could continue. An hour after I went to sit and prop my knee up and when I got up I couldnt put much weight on it.

It started swelling that day. I did RICE and now I can walk ok, I find it hard to walk upstairs and going downstairs is very painful. It think the swelling has gone down a bit, it is still bruised. It hurts to touch and is the inner side of the knee. Is it likely to be just brusing or something else?

Sorry for the long post, thanks.