I take provera 10mg last month December 9,2011 to be exact, and then I have my period after 6days (december 16,2011), my OB told me that if I take it, it will regulate my menstruation but I have a missed period this month because I am still breastfeeding but not pure breastfeed, my baby is mixed feed. I take pregnancy twice and it's negative. Does breastfeed can make my period irregular? I am just afraid to get preggy again... Some advice please.

Yes breastfeeding can make your period messed up.