Does Taking Diaformin Tablet Cause Diarrhea?

I was prescribed 850 mg of diaformin. After taking two doses I had bad diarreha and was all the time feeling vomitish. I was taking glucobay 100 mg before but when my GP saw that my fasting glucose reading went up 7.3, he decided to give diaformin itself. It is now the 6th day and I still feel vomitish and back stomach.