Your question is outside the scope of this Forum. One of us is a pediatrician, the other a child mental health clinician. Our area of focus for the Forum is on issues pertaining to child behavior and childhood/adolescent emtional and psychological functioning. We also concentrate on issues of normal child development and issues pertaining to parenting.
Your questions need to be addressed to your OB/GYN doctor or nurse practitioner. Please communicate to them your worry. You might even give them a copy of the note you addressed to us - it is a clear statement of your concerns.
Dear Samantha -
I agree with the answer already posted. I would encourage you to seek the answers to your questions from your obstetrician/gynecologist. There are many things that can cause irregular menstrual cycles. I'm afraid as a Pediatrician, I am not qualified to answer for you. Good luck -- Dr. EV.