I had unprotected sex four times this month. I m a twenty one year old. One of the days i had sex was my so called fertile day . On day 29 of my cycle i began what i think was my period. my periods have always been very heavy and last seven days, by heavy i mean having to use a tampon and a pad and having to change it every couple of hours. This period was completly different it started off like any normal one small bit of normal blood but never got heavier, it then changed to brown blood and was gone after three days. This has never happened to me before, cycles always very regular. I experienced very little cramps which is also unusual. Since then i have been very nauseated and vomited on more then one occasion. I have been urinating frequently and am constipated. I have also noticed a major increase in the amount of discharge i am having. In the past couple of days my breasts have become throbbing, tingly and heavy. I took my first pregnancy test two weeks ago and it was negative and another one this day last week and was also negative. I really feel pregnant. Whats going on?????????