Breakthrough bleeding on Medroxyprogesterone?

i am currently ttc and i dont have regular period so my doc put me on medroxyprogesterone(provera) to help regulate my period and he also put me on clomid. i do have pcos. the second day i took the provera pill i have light bleeding the it stopped now i 'm on my fifth day and i'm bleeding a little heavier. is this normal? just wondering who else has experiance this on these meds.