severe abdominal pain/chills

[Holly1589]

For the past 4 months, I've been suffering from this really weird stomach problem. It comes out of literally nowhere and only happens late at night between 1am - 2:30am. First, it starts out where my stomach feels a little weird, then I end up having to go to the bathroom, and then these intense chills/shaking occurs for about 30-40 minutes. After this whole ordeal is finally done, the next day I feel generally crappy and like I constantly have to go to the bathroom. It's an on and off thing, so one day I'll feel fine and the next I'll feel horrible. It also only happens about 1-2 times per month randomly. I've been to a few different doctors, I have had a colonoscopy and a CT scan, which both came back normal. This whole thing started off as what seemed like a stomach flu type thing with severe diarrhea, and then turned into this. I also frequently feel lower left abdominal pain with this thing in the exact same spot every time, and going to the bathroom does not relieve it.

I have absolutely no idea what it is, I'm going to another specialist to see if they can figure it out.
What could it be? Could I maybe have some sort of parasite? ( I haven't been out of the country, so it's probably unlikely, but it could still happen) Has anyone felt anything at all similar to this?

I've been searching high and low, but I can't seem to find an answer and I'm really worried because I've never had something like this and I just want to feel completely better :(

[Ratnakar Kini]

Hi,
Was stool test done?

[Holly1589]

Oh yeah, my gastrointestinal specialist said at first he thought it might be colitis - but I don't think that's the problem. All the tests I've undergone came back normal.