Suddenly don't want to eat

My baby is 6 months and 24 days. We started eating on the day he turned 6m. Introduced only mashed food and Cerelac when I dont have the time to prepare along with breastfeeding and FM. But then 3 days ago my mom suddenly told me that he doesn't want to eat. at first I thought it was a just a phase so I let it pass and just told her to just make sure he drinks his milk. But today as I tried it myself, He really doesn't want to eat. He gags and vomits the food out. Kahit kaunti pa lang ang naisusubo ko. Nag aalala ako. I read an article, that maybe it was just a sign of teething. Is it really a sign? Could you give some tips and advice on how to make my baby eat again. Thank you.