Will i still be able to have kids SOMEONE ANSWER PLEASE HELP me out I really want kids?

I got my first deop shot in aug 2010 and my second one in november i had little bleeds nothing serious but i was going to get my third one in feb, but i didn't cause i had really bad terrible cramps and sometimes a little bleeding and i had all the pregnant signs but all tests came back negative and i also got a blood test n it came back negative and since feb 2011 i have not had a period ever i get all the cramps and period things is this normal what should i do cause i was to have kids and i haven't had a period at all someone please help me out someone please give me advice and things to do like i feel cramping and my back be hurting and cramps and tender breast, will i be able to have kids and what should i do can someone please help