Discharge crisis!?!?!?

Abree
Hey guys I need some advice. So since the 18th ive had gross brown discharge that doesn't smell too great either. For the last to days its been more red and pinkish so I figure its my period and im just spotting but its been 11 days. Im 15 btw. Im also sexually active with my gf so this kind of sucks. Should I make a gynecologist appointment to be safe for am I probably fine and overreacting? Please help!!!!