I Have Been Having Strange Feelings In My Stomach And Irregular Periods. Suggest Me Remedy

i have taken several pregnancy test and they all came up negative. July 2, 2009 is when i had sex with my ex. and from that point i have been having strange feelings in my stomach and i have been having irregualr periods. to tell you the truth i don't know the date of my next expected period. i went to the doctor and they ran test on me before but that last time they didn't test me. i am not in a rush to have a child but it's just been unnormal to feel how i'm feeling. sometimes i would puke i wouldn't say vomit. and alot of times i would feel movements in my stomach and just recently i felt something push up against my stomach while i was lying down and it stayed there then it went back down.