So, my doctor did tell me that you can't give yourself an issue by eating your own poop. I know that is gross, but true. Found it out with my first son that took off his diaper and was playing with his own poop and some got in his mouth. My doctor was worried about ME but not my son. Here is a quote from Seattle Children's Hospital "Eating your own feces is always harmless. All of these germs are already in the child's body and digestive tract. Some young children in diapers may do this at some point. This will not cause illness."
So, ya, not cool but at least it's not a big old E coli infection like it would be if he forced HIS feces in your mouth.
But the rest of it? Sounds wrong. That you had diarrhea from the depth of his penis? That you are vomiting? I WOULD see a doctor to make sure you don't have an internal injury. And frankly, never have sex with this man again. Actually, this wasn't sex. This was him hurting you for his own gain. Making him darn close to a rapist. Get away immediately. And if you are hurt, you could consider pressing charges. Sounds like a monster to be honest.
Let me know if you can get to a doctor.