Hello, i am a sexually active 22 year old. I am on Birth Control and with that my periods are rather on point each month, however lately, I've been having some very light spotting after having sex, but it goes away soon after. My concern is, about a week ago, I finished my period and I now started bleeding again heaving and very very dark, with pain and pressure, as if I'm having another solid period. This has never happened before. What can this be? Please help, thanks!