What have I done?

Was out last thursday night messing around, missed a double and somehow came down with all my weight on my toes. I believe I had both knee's locked when I landed. Was really an easy fall but horiffic pain. Had to have help out of bindings, pain went from left knee to ankle then lower leg went numb. Got back on land and had pain when weight was put on it, then right leg felt similar. Doctor not sure what's wrong, said he could feel start and stop of the cl's in both knees, xray's looked good, but steal great deal of pain in left knee and high ankle while trying to walk, right knee just sore when extended fully. Knees feel fine while slightly bent but hurt when straight or bent past 90degrees. Any idea what I'm looking at, just hyper extension?