I think you are right to wonder if the cramps are really related to your period. The most common type of menstrual cramps occur a few days before and the first few days of the period. Sometimes, some women will experience briefing cramping right around mid-cycle a few weeks before the period that corresponds to ovulation - this also is normal.
However, if the cramps that you have occur throughout the month, then these are unlikely to be related simply to your period. There are still several other gynecological conditions that could cause this kind of cramping, including endometriosis
and infections of the female organs. However, there are also a lot of non-gynecological possibilities. These would include things like constipation, lactose intolerance, irritable bowel syndrome
, and celiac disease (an intestinal disease caused by intolerance to wheat gluten).
I would suggest that you start by going to see your primary care doctor
. They will be able to perform a complete physical examination to help determine what is going on. Make sure to mention your sexual habits, menstrual history, and symptoms related to appetite, weight loss or gain, and bowel movements as well as any thing else you think might be important. Good luck!