You may be intollerant. I know it took almost a year before I could slowly introduce Greek yogurt into my life again. I used to vomit up yogurt from a day or two days prior when I was at my sickest. Some of us are just plain dairy intollerant for awhile. I would recommend trying life without yogurt and see if that helps. You can always try reintroducing it when you are farther along in small amounts.