Me and my boyfriend have sex everyday we had been doing that since March well at the end of the month my period. Came on but in April it came on in the second week I think on the 15 the..in June it did not come on but on July 5 it came on and lasted 5 days..in August it did not come on and now we r in September and I'm still waiting I took a pt test it was negative..my boyfriend said he has been in relationships that lasted for years and they have not gotten pregnant.he do not think he can have kids because his ex had kids after they broke up..I have been cramping like my period is coming on for the past couple of weeks and sometimes feel nauseous after I eat sometimes or light head.wut could it be