HI,
    Thanks for asking. I have read & understood your complain.
    Stomach pain with 
diarrhea & 
vomiting  occurring multiple times in 
pregnancy.. indicates-
    - Over eating,/  indigestion/bowel infection. 
   You should get a check up to analyze the cause. A check up by your treating doctor, investigations like stools examination routine & microscopic would throw light on the cause , followed by specific treatment,
   You need to-
   - Take small & multiple servings of food in a day ( 4-5 servings in a day ) with 
proteins, carbohydrates, 
Vitamins & minerals ( vegetables, salads, 
  fruits )
  - Avoid over eating/ irregular eating or late night eating / alcohol.
   - eat fresh food avoid eating left over food, stale food.
   - Avoid immediate sleeping after food,
   - Do regular moderate exercises/ walking.
   -Take medication advised by doctor regularly.
   Thanks.