Have Crohn's Disease, No Mirena Coil Fitted, Bloating, Nausea, Diarrhea, Hip Pain, Lower Back Pain During Periods. Is This Normal?
Sorry to hear that your problem is taking its toll on your daily life. Your history is very typical of endometriosis (when your menstrual epithelium is located at other locations and it bleeds during your periods). It is because of this reason that you are having bleeding through your back side every time during your periods. The pain is also suggestive of endometriosis, which can lead to incapacitating pelvic pain, back pain and nausea. It is very unlikely for Crohn's to give rise to these symptoms only during your menstrual periods. Another point in the favour of this condition is that you did not have these problems when you had a hormonal ring (merina) because it suppresses your periods.
My advise to you will be to visit a gynecologist immediately and get yourself examined thoroughly by her. Sometime this condition cannot be picked up on MRI and requires diagnostic laparoscopy (putting in a scope in your belly and visualising the problem).
Hope this gives a direction on how to pursue further. Please let me know if you still have any doubts.
Hope you get well soon.
Take care.