On April 27th i had intercourse with my boyfriend but he was scared he didnt pull out on time. Lately ive been feeling weird. At first i thought i had a stomach virus, which the nausea has since gone away…but now i feel like i have the flu. Im just very tired, have a low fever, i get headaches and feel very weak. I have also been constipated. I took a pregnancy test on May 8th and it came back negative. I was supposed to start May 11 which by the way i am always on time, it is now may 13th and nothing at all. I do feel bloated, slight cramps, but somehow they feel different, i guess not as strong and i get backaches once in a while. Could this be all in my head?