About Masturbation, and bleeding.

Im 19 years old, and have been masturbating for around 4 or 5 years now, im a virgin. Well technically, i have never slept with a man. I am also obese. Everytime i masturbate, i seem to bleed a bit, after i do it. Not during only after, and only just a bit. It happends everytime. I dont think anything serious is wrong because i do masturbate with objects sometimes, or just use my fingers. Im also irregular in periods, and i though it might be backed up and that causes the bleeding. Because i only have a period once every few months, and even then the period could be a few days, or as long as a month. Please Help,