help - dr has no answers

Hi - I am a 31 year old female, healthy, no meds. Over the last three months I have had bouts of severe abdominal pain (we are talking incapacitating pain), usually with vomiting and sometimes diarrhea. This lasts between 6 -24 hours. The pain starts on my left/middle side below the breast down then radiates down and toward the right.

This has happened once a month since August - last night I went to walk in clinic and they checked me into the emergency room and then overnight in the hospital. At first they said it was an appendicitis  - as my appendix looked large on ct scan... my white blood count was also elevated. Today - my white count is down, my pain is gone, and they are discharging me.

Anyone have any thoughts??? The drs said they don't know what it could be.

many thanks for your help,
-w