Stomach bug or food poisoning

My almost 5 year old was just throwing up last Saturday. He was recovered by Sunday and fine all last week. Then starting today (Sunday) at 4pm until now 11:50pm he has thrown up 8 times and had diarrhea 3 times. The diarrhea is like a bright dark green and smells AWFUL like way worse than normal diarrhea. We went to outback steak house Saturday evening and he had chicken tenders so Im just wondering if it could be food poisoning. Only thinking that because we all just had the stomach bug last weekend starting with him first. Didn’t think you could get it again so fast. I’ve been pushing sips of water and Gatorade but nothing is staying down. I fully intend on taking him to the pediatrician in the morning just thought I would reach out in here and see if anyone had this happen before, like a week after stomach bug.

Also had a zofran of his that was still in date and gave him that around 7:30, then he continued to throw up and have the diarrhea