What Causes Frequent Vaginal Bleeding?

it's been a month or little more the blood has been seen most of the time and it's making me think alot and couldn't concentrate on anything.At the same time I am also having sex with my boyfriend, is it harmful for me, why blood is being seen time to time even it's not my menstruation time, is it something related with much sex or oral sex alot? Can you help me please?