Help😩

My baby is four months and is breast fed. Yesterday I ate a meal I got from the grocery store for dinner. I fed my baby through the night and in the middle of the night I was going to the rest room with sever diarrhea. The next morning as soon as my son woke up he was grunting really bad and crying. Throughout the day I felt as if I had to throw up but nothing came up but I went to the restroom at least 3 times already today. My son just screamed for a hour straight and I literally had to rock him to sleep. I'm figuring his stomach is hurting severely because mine is. I just don't know what to do. If I should take him into the er or try to give him water. I feel the more he nurses the more his stomach will hurt if kindle is still hurting. Does anyone have any experience with this kind of issue?