Should be indigestion. I experienced this 2 times around 26 weeks too. Recall what you ate that caused the diarrhea and vomit. For me I suspect I took stool softener (Lactus) and eggs for breakfast. Could be lactose intolerance for my case, not too sure. Anyway mine stopped after 2 times. So if yours persist every meal everyday then it’s not good as you can get dehydrated, not good for baby. Make sure you drink up and compensate for the water loss! Go gynae and let him or her know your condition will be the best.