my girlfriend recently just had a spot of blood in her underwear, and i am wondering if i should be worried. she is on the pill and takes it at the same time every day, but about a week ago she missed two pills, but then took two the next day, since then she has been on time and hasnt missed a pill. we are pretty sexually active, we have sex almost every day, but i rarely ejaculate inside of her. maybe three times in total. anyways, yesterday she got a spot of blood on her underwear and i am worried, should i be? is this common? what are the chances of her being pregnant