Recently my body has been rejecting sugar; what does this mean?

Sometimes instantly… I had some reese’s peanut butter cups the other day and had to evacuate my bowels almost instantly. In that case, maybe it was too much – those mini’s are addictive. However, the other day I had a single peppermint paddy (sp?) and I felt ill for hours. So, I was thinking maybe just all that refined sugar was the culprit. But now, I just had some dried cranberries (not too many) and I’m all bloated.
I have cut a lot of sugar out of my diet… maybe I’m just super-sensitive now? Frustrating, because it’s nice to have a treat now and then. What gives?