Help?!

Hey ladies!

Just wondering if anyone has had an experience like mine, and if they could share some insight. I am 31 years old, and my past 2 cycles were wonky, to say the least. I skipped 2 cycles waiting on the one I am enduring now, and the previous was 1 1/2 months late as well. The time between seems to be getting longer, and when I start there is a pretty heavy flow accompanied by sever cramping. I am not on any birth control, but underwent a tubal ligation about 5 years ago after the birth of my son, who is my 2nd child. In the past, I've been quite regular, but DID deal with sever cramping, severe bleeding, and passing quarter sized clots. I have already contacted my doc and am awaiting the appointment date. Having answers or theories about what's happening helps soothe my anxiety. Your opinion could be very helpful! Thanks everyone.