I Banged The Top Inner Side Of My Knee On

I banged the top inner side of my knee on a screen door jack. It cut me a little but the pain was horrible. It seemed to have taken over my entire body. I tried to walk it off but immediately got naseated, light headed, and started sweating profusely. My fiance said it seemed like I had a tiny seizure then passed out. It was definitely a feeling I never want to have again. Why would that happen just from banging my knee? Done it a million times on harder things but never has this happened. Can someone tell me?