I have a thick clumpy white no smell dicscharge every month before my period. what is this? i've tried monistat and i don't think it's a yeast infecti

Discharge: It likely is a yeast infection but could be a few other things. the pH and bacterial make up change during the cycle and this may be why it is happening. You doctor can do simple test to diagnosis and treat it.

Normal?: The amount and type of vaginal fluid varies widely between women. If "every month" means no change for more than a year, maybe nothing is wrong. If more recent or in doubt, see a doctor, especially since self treatment for yeast didn't work. Possibly an STD like gonorrhea, chlamydia, or trichomonas, if at risk. Maybe nothing is wrong, but better safe than sorry.