How do I keep loving this work when it keeps hurting me?

You did not take this work for the pay. You took it for the animals, and the pay is thin because you knew that going in. Say that plainly to yourself — it removes one lie you might be telling. The bite, the bad day, the owner who cannot speak through their grief — these are not interruptions to the job. They are the job. Expecting a clean day is what wrecks you, not the hard moment itself. You are not doing this alone. You have a pod. A weight split four ways is not the same weight carried by one person pretending they are fine.