unknown reason for feeling sick & nausea

:$ im 22. i am sexually active but use protection EVERYTIME. i spotted for like a day n a half early last month(may) but havent had my menstrual cycle since. im not very regular n e ways so i wasnt worried at first. if had a loss of appetite, stomach aches, my lower abdomen feels heavy sometimes i feel very bloated, urinate frequently, am very thirsty all the time, nausea. i notice i get dizzy & neauseas more often when im hot. what could cause this? should i be super worried? any ideas why im feeling really sick? :$ :'( ? %-) :-) 8-|