What Causes Lack Of Periods Even After Stopping Depo Injections?

hi i had a baby in nov 2007 which i breastfed so had no periods, then started the depo injection in feb 2008 still no periods at all, i have stopped the depo injection in jan 2010, with no periods still. but have been getting cramps in the evening still no period, will stating the pill tablet start my periods? 0r does it sound like i will be getting one soon, my husband and i really want to be pregnant by the end of the year, thanks rachel