Yep, rabbits are not rodents, they are from the Lagomorpha family and are treated differently to rodents. They are actually more similar to horses! I would find a new vet, you need one called an “exotics vet”.
Is your bunny pooping now? As well as eating.
You need to get your rabbit to a vet ASAP WITHOUT DELAY! This sounds exactly like GI Stasis which can kill them within a day. Please see a vet that specialises in rabbits who can do their best to get your bunny’s gut moving again, relieve pain and get him eating. More details here but please go...