I'm a 20 year old female. For about 4 days now I've been feeling lower abdominal cramping, kindof like menstrual cramps sometimes, but they started about 10 days before my period is due. I haven't been able to use the bathroom in a few days now and I feel super gassy and bloated. I have a back ache and a constant headache. I feel very weak, light headed, and I have no appetite, when I force myself to eat I feel full very quickly then sick afterwards. I'm also getting pains around my chest and around my stomach. What could be wrong with me?