I ve been experiencing nausea , a fluttering feeling below belly button when i lay on my back or side, a numbing feeling in my sides and slight muscle cramp in side, lightheaded, a little bloating , moody, exhausted..... changes in menstrual cycle for past five months, very light and brown in color, only lasts 3 days, normally very heavy and lasts full 5 days, took a pregnancy test months ago but was negative. Don t think i m pregnant, what else could these symptoms be?