You did the right thing when you learned to express bowel and bladder. I presume the vet prescribed the antibiotics for a possible bladder infection, right? I think the vet is describing IVDD, right?
Looks like you are doing everything right, except I'd suggest crate rest. I am not a vet, but the owner of a paralyzed pet. Did you read about steroids and crate rest? Crate rest normally lasts 6 to 8 weeks- NO cheating; no dragging about the house.viewtopic.php?f=4&t=10626
The vet told me pretty much the same thing about 4 1/2 years ago when my dog Schnitzel became paralyzed from IVDD. That's right, he has been paralyzed for 4 1/2 years, and not been ill. I think most people give up waiting for the pet to recover and vets are VERY willing to PTS. You CAN keep your pet.
Don't let the vet tell you it's NOT possible to KEEP your pet healthy and happy. Dogs handle rear paralysis better than their owners
Wait a bit longer for the wheel chair after you are finished crate resting. Paralysis is NOT a death sentence.
Let us know how you are doing.