Since I have started my periods, I always have sever nausea the night before and then for the whole time my period lasts, it gets a lot worse at night, my periods last between 12-14 days, due to the nausea, I don't have much of an appetite during this time, i also get a very bad stomach, cramps and an upset bowel, it makes me feel very weak, shaky and drained, my doctor says there's nothing wrong with me, he hasn't even ran any tests. Is there anything I can do?? Any idea whats wrong with me, I can't take it :( I'm only 20.