I don't know why my period hasn't came yet!

I haven't had sex in a month and which i am.not trying to get pregnant. my husband wears condoms always! My period was supposed to come may 7th. my last period was April 6th. I have been on flagyl for bacterial vagnosis but my ob/gyn.doctor put me on clindamycin for bacterial vagnosis since flagyl wasn't touching it. I don't know if those two can make you have period delay but I have gained weight and plus I may have mommy stress too. it throbs down there and sometimes like I'm fixing to start soon.but nothing ever comes.