i am a 14 year old girl, and after i eat something- like a toasted sandwhich i get severe stomach cramps near my bellybutton and all around mmy stomach aswell. the pain from my stomach makes my lower back hurt too,it gets so severe that i cant stop crying, and that i sometimes wake up in the middle of the night. i feel nausea aswell. i cant throw up, i dont have diahrreah but im a little bit constipated at times too. the pain goes away after hours, but returns when i eat something. is this appendicitis?