Find a new vet.

The snake looks fine to me.

When I have small snakes, like my two Kings right now, I feed twice a week, Wed and Sat. I prefer to have a set schedule than a rotating 5 days. But that's the closest I'll feed.

If the food source is about the same or slightly bigger than the snakes thickest part it can eat it..... It can actually eat larger but that's not recommended. People often underestimate what their snake can eat.