Diagnosed with mesenteric adinitis 3 weeks ago in er pain is now all over in my abdomin. what do i do now?

You should: see a doctor to sort it out, because there are literally hundred of causes of abdominal pain. If the pain is severe, you should return to the ED.

Go to the ER: Mesenteric Adenitis is a diagnosis of exclusion meaning when all other possibilities are excluded then perhaps your pain is from swollen lymph glands in your gut. It can have several causes but usually doesn't last long except when caused by mononucleosis. Diagnosis of abdominal pain can be complicated & if you continue to have pain as bad or worse than before you need re-evaluation NOW in the ER.