Possibly Colitis? Any ideas?

Hello, I was recently released from the hospital following 2 days of tests to find out whats wrong with me. I woke up 3 days ago with severe upper right abdominal pain and severe diahrria.

They did blood work, xray, ultrasound, which all came back normal.

They sent me home with a stool kit, which I dropped off tonight.

Im not experiencing any fever, but have had a migrane (migraine), the abdominal pain and diahrria still along with extreme fatigue.

He mentioned a possible MRI or Scope if things dont improve, but how long should I wait if it's a possibility that I could have something like Colitis?

Thanks for your imput