Bleeding during sex!

So i'm 14 and a year ago i had sex with this one guy i use to like and i started my period when i lost my virginity to him so i'm guessing i probably popped my cherry. so then ive had sex with my ex 2 times (once when we were together and once after we broke up) and the first time we had sex which was april of last year i didn't bleed but when we had sex in the end of june this year i did bleed (i've had sex with a condom on all times i've had sex) when i look online it says i have a STD but i haven't had unprotected sex or ever given head and i can't see a doctor because i can't tell my mom. Does anyone know what it is or if i'm doing something wrong???