How Can Irregular Periods Be Regulated?

Hi my name is Tammy i'm 29 years old and have 6 children and my period has always been regular. I had my twins in 2009 (june) and everything was fine after that (i had a c-section) January this year my period was on time but in february i was 2 day early than much an extra 2 days early so that would make it 4 day from january and than a week early and after that a week and a half late and it keeps on happening and i'm on the pill too. but my periods are so messed up i don't no when to take it and when not to as with all what happening i come on for 4 days come off for 3 and back on for another 4. what do i do? alth queries right now ? Please type your query here...