Last month i had period pms w/ diarrhea and the week following my period had me constipated. it cleared but now im constipated again. is this normal?

Hormones: This may be from changes in the hormone progesterone. One of its effects is to slow down the contractility of smooth muscle. In your case, when your progesterone level's high, like in the two weeks before your period, your G.I tract slows down, causing constipation. Then, when the level's low, like shortly before, during & right after your period, your GI tract speeds up, causing diarrhea.