I tend to have more pain around that time of the month too. But 6 years ago it was really bad and it ended up being an abcess. Thankfully, I was able to avoid surgery. I remember the doctor talking about the differential diagnoisis during morning rounds and he mentioned that if you press down and it hurts, it is more likely to be Crohns related. If it hurts when you let go, it's more likely appendicitis. Either way, if it continues, you should definitely go to your doctor. Good luck!