Terrible reaction to buffered vitamin C.

Hi. I have various ailments mostly chronic fatigue and stomach problems. I had tried taking regular vitamin aka ascorbic acid capsules but they seemed to make very little difference. Neither positive nor negative effects, even at high doses. So I decided to try Solgar buffered vitamin C (calcium ascorbate with Rutin and bioflavonoids), which I read us supposed to be gentler and generally better form of vitamin c. Boy oh boy I had the worst reaction! My stomach burned and I had acid diarrhoea for five days. I had taken two 500mg capsules and by the evening I was burning inside. And when I ate it burned. This really surprised me as I always read that the regular vitamin c is worse on the stomach, and buffered is gentle.
So why did I react like that? Was it a detox reaction? Was it a good sign? Or should I steer clear of the stuff?
Thanks in advance Tweet