What Causes Abdominal Cramps During A Menstrual Period?

I am 35 years old, have been pregnant once but aborted. I have had fibroids removed b4 and have been married now for 8 years without getting pregnant. I have never had delayed periods within the last 8 years but my last period was late for about 8 days and I am having cramps on the right side of my tommy. today is the third day of my menstral flow. what could be wrong. although I started drinking lemon about 2 weeks ago