We had manual sex the second week of january, so that was about three months ago. We were both wearing pants and underwear. She has had two normal periods since then and we havent done anything since. She was supposed to get her period around March 22 but it still hasnt come. Howevever, she did have a dark brown discharge a week ago but her period did not follow. She has taken four pregnancy tests and all of them came out negative. She is currently studying for the GRE which is in about a month, could that be delaying her period or even causing her to miss it or is it possible that she is pregnant? We are quite sure that nopre-ejaculate was involved as we never took our pants off. Thanks.