Aah, good luck with the knee!! Hopefully everything is fine and it's just a bit angry from the fall. Let us know!
I had a scary fall about 18 months ago where I fell, it hurt, once I started moving I realised I was ok, I got up and skied another two runs, and only once I took my skis off for a break I realised that I couldn't really walk on it at all.
I was sufficiently unnerved to immediately pay a lot of money for the doctor at the ski area med center to look at me and do the manual tests on my knee to check for torn things. It ended up being fine though!! They said it seemed to be a mild LCL sprain and told me to take it easy. Since I couldn't walk but I could ski, I skied cruisy groomers the rest of the day out of sheer idiocy, and then took a week or two off skiing.
Anyway the conclusion here is that we all worry a lot about knee pain so you're in good company
I could not even wait two days to see my physio back at home, I had to get my fears assuaged RIGHT THEN AND THERE at the ski area!!