cramps, nausea and it still won't quit what could be up?

for some odd reason i have feeling really sick to my stomach for the past few weeks, maybe even a month. yesterday i had such bad cramps and i really thought i was getting my period, but i didn't. last night i started to feel a bit dizzy as well, but i think it was because i was so tired from the long dy of school that day. this morning i get up and my stomachs twisting like a cyclone for no reason. i tried to eat something but the smell of it made me feel like losing my dinner from last night.. any ideas of what could be wrong?