Has anyone ever experienced this?

Has anyone ever experienced this? The baby has been refusing to eat for 5 days straight. He drinks one formula with a couple of tablespoons of unsweetened porridge added. We started giving him pieces of vegetables first, but he threw them up, then cried and then cried again. Then we went back to buying premade porridge, but now it's 12+ with some rice puffs. And he doesn't even eat the porridge anymore, holds it in his mouth and won't swallow. It stays in his mouth until it turns into water, then it comes out on its own. I don't know what to do, thought maybe teeth, waiting, waiting, waiting, so much porridge ruined, poured down the toilet.