what's my problem

So two weeks ago I had a period and after I had some pms symptoms which freaked me out a little and when I made a post on here someone told me to still take a test . I took a test and it was negative *i guessed that * but I'm still having problems . On and off through the day I'll feel sick .. Sometimes I wake up out my sleep extremely nauseous but I never throw up and I'm ALWAYS hungry . My back and head have been hurting and sometimes I'll have heat flashes . Any suggestions ??