Am I Pregnant??? Or are these signs due to something else! please answer!?

Okay so I am sexually active, and i had sex a couple weeks ago, and it had been a long time so i bleed after a lil?. I'm on the birth control pill, and use the pull out method as well.. ( i know it doesnt work that well thats why im also on the pill...and cant use condoms cause im allergic. My Boobs are sore a lot cause of the pill so thats nothing new... the signs im worried about is Vaginal bleeding, Lately everytime i orgasm i spot the next day, and sometimes randomly spot blood, with a brown discharge. Also the last two weeks i've been constipated. Do you think im pregnant or its just something else?