Still bleeding days after first time . help!?

so...i'm looking for some kind of advice. three days ago i had for the first time.it was very painful and i experienced bleeding. the morning after, there was only a brown discharge on my panty liners, which i umed it was old blood.in the evening however i started bleeding again and that was definitely not just old blood, as it was bright red.now three days have ped and i'm still bleeding. i've been taking Yaz(birth control) for some time now, i have regular periods, so i'm sure this is not period blood. + i used protection during the ual . i'm afraid this might be a laceration (it stings a little when i wash but otherwise there's no pain) ...i have no idea if i should wait and see if it pes or if i should panic and go to the obgyn asap. is this normal? could this be a laceration?if so, how long does it last?and what can i do to prevent the wound from opening over and over again?