As someone mentioned, a food diary would be good. Also, I read that the digestive system is at it's peak in the morning, less so as the day goes on. If true, then having no problems in the morning makes more sense. But still something is wrong. Good luck in running this down. Mayo has a long list of possible reasons for vomiting: https://www.mayoclinic.org/symptoms/nausea/basics/causes/sym-20050736