Is there something wrong with my vaginal muscle?!

im 17 and at night i felt like i wanted to pee then my vagina got tense and started pulsing like i was almost ganna get an orgasm so i tried to calm it down then i went and peed, after i peed the muscle was tensing up again, i couldnt control it lasted about 5 seconds, whats wrong with my "downstairs"? i remember this happened like twice a year since i was 15