Suggest Remedy For Pain In Right Side Of Abdomen And Groin During Periods

Hi, I'm 37 years old and trying do get pregnant. My last period was January 31. About a week ago I had cramps and I thought I was pregnant. But last monday my period came and a coudn't go to work yesterday afternoon and today because I have severe cramps and pain especially in my right side and groin (right). It is the second time it happened since I started trying. By the way, my period comes after 28 days and when I started having cramps it is always on my right side. What it can be?