A little over a week ago, I was having sex w/ my bf and right afterwards when I went to the bathroom there was a tiny bit of diluted red blood, maybe a drop, on the toilet paper. I was on top and it was somewhat vigorous, so I didn't worry too much. But it's continued to occur since, even after 5 or so days w/o sex. It's not much blood, and less than the first time, just a few tiny spots of pinkish blood on the toilet paper. It doesn't seem to be mixed in w/ the other fluids, and it's not drips or drops, instead I notice it mostly when I press the paper just inside my vaginal opening. Within a couple of minutes there's nothing, and I've had no other signs of bleeding except during penetration. No other symptoms in the area, no itching or burning or any other irritation, no change in discharge, smells, nothing. We are both STD free as far as we know (recent testing for everything except herpes, but neither of us has ever had any symptoms, and we use condoms.) I've examined myself with a mirror as closely as possible but can't see anything, though it's hard because it's the interior of my vagina and there's obviously bits and folds of tissues.
Could this just be some small tears that have been slow to heal? My bf is somewhat thick, but I've never noticed anything before and we've been having sex for 4+ months. I'm paranoid so the fact that this keeps occurring bothers me. My period is due in a day or two, and if it happens again after a week without penetration, I plan to go see a doctor. I was just hoping to get some opinions on this. Thanks!