If your disability is psychiatric your are absolutely entitled to request a reasonable accommodation that could include owning a pet.
Whatever you do, don’t try to sneak the dog in and hide him. That’s a recipe for disaster.
As the old saw goes, life carries with it few guarantees. Maybe that’s why many of us are so attracted to dogs. They usually offer unconditional love, unlike landlords.
You are in breach of your lease and could be evicted for having your pooch because it seems like the lease has a clear “no pets” provision.