I dislocated my kneecap and I'm taking part on a relay in school next week. HELP!?

I dislocated my knee cap this morning, then I moved it back to its right place. I had a little black out and I couldn't walk. I felt dizzy, sleepy and extremely thirsty after that. I still feel a slight pain when I straighten my legs. It happened last year as well. We went to the doctor and I don't think they believed me when I told them my kneecap moved to the side. I also don't remember how long it took for me to be able to run again. Anyway, I'm taking part in the school's relay next week and I really want my knees to heal fast. Please don't tell me to back out, its really important to me. Please Help.