whats going on???

Im 18 and had sex for the first time 4 days ago (Wednesday night). We used a condom which was slipping around slightly during sex & he didn't cum inside me. On the night I bled slightly & it barely hurt. The next day I didn't bleed at all (Thursday). But since Friday I have been bleeding a light pink blood that looks like blood mixed with pee or something. It's got slightly heavier last night today. People are telling me that it's normal after my first time but I'm not sure if it is for this long?? I can't go to the doctors without my mother knowing so that's not an option. What could it be?