3 months ago I had a lot of unprotected sex but using the “pull out” method. Since then I have had my period 2 times. This third month I haven’t gotten my period at all and it’s been 8 days. I went to the doctor to get birth control and they took a pregnancy test and I came back negative. I hadn’t gotten my period for 3 days so I just decided to start the birth control then. I have been taking the pills for 5 days, no period for 8. I’ve been stressed out for this past month so could that be why?