I am taking Source CF 2 times a day. I added D3 (2,000IU) a couple days ago. I think I had a bad response to it even after the first dose: severe abdominal pain started up high and went around to my back. Has anyone else had bad reaction to fat soluble D3? A CF doc I had a consult with recommended it. But I'm rethinking it now. Any input would be appreciated.