Gassy Batch

I tried brewing 1 gallon of hard cider with no added sugar, just plain store bought apple juice with ascorbic acid added. I added 1/2 teaspoon of Red Star Cote Des Blancs Wine Yeast. It only bubbled for a week and a hald but I racked it after 2 weeks. It tasted so bland, I added one can of frozen apple juice concentrate. I drank 4 glasses and felt no alcoholic effect and all night I was bloated and uncomfortable. Any thoughts?