Hi I had sex July 13th and since then I have gotten 4 periods. The first was 2 days late and was super heavy with terrible cramps to the point where I threw up lasted 6 days. The second was one lighter than usual and 2 days early with barley any cramps lasted six days. The third was 4 days early 1 day shorter and still lighter with light cramps lasted 5 days.The most recent the fourth was a week early lighter than normal and still barley any cramps lasted 5 days. I don't think I am pregnant because I took three tests and they were all negative. The reasons my periods could be different is because of excerise and dietary changes, however there is still a part of me that believes I could be pregnant. Is there any way? My periods are normally 4-7 days. Heavy periods usually can fill a pad or tampon in 3 hours. Takes 6 to fill one now.