I Fell On My Knee About A Week And A

I fell on my knee about a week and a half ago in an asphalt parking lot. It bruised across the front of the knee cap, but not in a very dark way or anything. Didn't really notice any major swelling, and don't seem to have any issues with normal activities. However, it is still very sore to the touch and if I try to kneel on it at all, I feel like I'm going to be sick (not from the bending but from having it touch anything). My doctor told me a while ago that I tend to carry water on my knees. Could that be part of the problem? Should I be doing anything to help my knee heal?