It would be important to know how many bowel movements you are having right now, and how frequently. When people are diagnosed with rapid transit problems, it is common to put them on medications that slow down the intestines. However, it is really common to overswing and end up really constipated!
Therefore, if you are having bloating, cramping, and infrequent hard stools, then this is probably what is going on. If so, I would call your gastroenterologist's office right away to let them know and ask for advice. They will probably, at a minimum, tell you to stop taking the loperamide, as that is the primary constipating medication. Once you have resumed a more normal bowel movement cycle, you can again begin playing around with the doses of the loperamide to slow things down enough, but without causing the constipation.
If the abdominal pain
is severe or if you have any other serious symptoms, such as fever, or vomiting, then this might be a different problem altogether that requires more immediate evaluation. In that case, if you can't get in to see your doctor
right away, you should go to the emergency room for evaluation to rule out things like appendicitis.