I am not sure if im pregnant sometimes i get my period every month but i also get it every other month. And me and my boyfriend have had sex a couple of times and the last time it was about 4 weeks ago and i havent gotten my period and and i have been getting cramps they come and go but i dont get my period,and this never happens to me only when i am really getting my period i start to get cramps i start two get cramps like 2 days befor my period but its been already 3 weeks that i get cramps but nothing happend. and i also feel like throwing up sometimes but i dont. and i am urinating constantly.