is there nything i can do to regulate my menstral cycle?

[mistys]

i have always been irregular after my son was born i got normal for 4 months now its back agian my doctor prescribed me provent yes it worked as long as i was takeing it but after the third month i quit takeing it now im irregular agian been tryin to get pregnant for 3yrs i know unless i get this worked out i can forget the precious baby i want so bad please help