Suggest Treatment For Vaginal Bleeding After Finishing A Period

I'm 21 weigh about 140 pounds and my height is 4'10''. I masturbated two days after my period ended and now I'm bleeding. The blood looks similar to a menstrual flow and it feels that way. Theres is no pain just the bleeding. This has never happened before and it's been three days now so I'm worried. I have never had penetrative sex before or tried to insert anything in my vagina.