Hurt my knee

[WackityWhiz]

about a week ago I fell (pretty hard) and landed on my left knee. I lit on a marble floor. When I run my finger across my kneecap, I can feel something. When I touch it, it sends tingles towards the outside of my knee. It's almost like a tendon/ligament (don't know the correct term) is injured. Is there a tendon/ligament that I could have torn on the front part of my knee?

Another thought I had is that I might have cracked my kneecap. Do you think it would be possible to crack your knee cap and still be able to walk around on it for a week? The only reason I suspect this is because it hurts pretty bad when I press down on it.

It only hurts when I touch it, so I'm guessing it's a _CL injury.

I'm going to the doctor in the next couple of days to get it checked out, just wanted to get an idea of what it could be first.