What Causes Lower Abdominal Pain During Periods?

I had a c section 3 years ago. Every time I have my period and poo I have severe pain in my lower abdomen, it is very severe, as bad as what I recall close contractions to be like. Should I go see my doctor about this or is it normal? I also have very very heavy bleeding during the first 2 days of my period with quite a lot of clots, if this is relevant at all?