What Causes Diarrhea After Drinking Water?

I had most of my thyroid removed and never was given any meds about ten years ago. Now I am experiencing hot sweats, flushing, headache, ibs, tiredness and hyperisem. It s like my body went haywire. My dr. Is keying in on ibs which I have had in the past with periods and when I had a gall bladder full of stones. After that was removed I got occasional diarrhea. After I had the flu last summer I seemed to have had ibs more often. Within the last few days I have been having diarrhea every morning when I drink water. This is when I got the other symptoms mentioned above. Would a thyroid replacement help?