Here are some things that have bothered my stomach being vegan. 1. Too much chocolate - you did not indicate you are having chocolate but just in case 2. Too much caffeine - maybe cut back on so much green tea and try herbal teas 3. Herbs in many vegan vitamins - I tried all of them and finally tried Megafoods which work great for me and do not upset my stomach. Unfortunately, they are the most expensive but my tummy is worth it. Maybe one of these ideas will help you.