Since when is this happening? Are any investigations done? Can you pin point an area of maximal cramping? How old are you? Are you on any medications? Any previous significant illness?
Just the frequency of these episodes (every two weeks) demand investigations like ultrasonography and may be CT scan of the abdomen to get the diagnosis. I would consider the following;
2) chronic intestinal obstruction; with a previous abdominal surgery, adhesions are very common
3) recurrent appendicitis
4) gall stones.
You should contact your primary care physician for these investigations, so a diagnosis can be established and further management is instituted.
Please feel free for your follow up questions.