I am 25 years old and I have been taking a birth control pill for almost 3 months now, have a couple days left before I can start my next pack of my birth control, for the past month now, I have been bleeding while having sex, I do not bleed during the day but only when having intercourse is when I have a fairly large amount of blood come out, tonight I took out my tampon and something came out on it, it was like a piece of skin about the size of my thumb, could someone please tell me what it is?