12 Days Late! Need Advice!

i went two months without my period after December and wasn’t pregnant. went to the gynecologist for pap smear in February . she also put me on progesterone to make my period start. and i got it in march about 5 days after i took the progesterone. now here is may and i missed my period last month. i went to the emergency room last monday and the did a pee test which came back negative. i’m not sure what’s going on. i’ve been having really bad diarrhea, sore breast/nipples, very fatigued, bad backache and random cramps that take your breath away. has this happened to anyone and they end up pregnant?!?