Hi, i have a very similar case to the one below. I had sex last night with my boyfriend in doggy style position, and to be honest it was very fast and hard. I had blood coming out of me just after. Do you think this could have been vaginal tearing? I know i do not have an STD as my boyfriend and I found out we had chlamydia a month ago, so went to get cleared up and took medication. This has now been 3 weeks since we took the medication. We followed all the advice from the doctor , so unless it has come back somehow or not cleared up fully, I can not see how its an STD again? I d just like to know if having hard fast sex really can cause bleeding like that? And can chlamydia return?