That is great that you are wanting to work in animal rehab. I have a friend that works in a vet clinic and she's allergic to cats. She's tried taking Benadryl and such but she still has a miserable reaction and says it's definitely not worth being sick all the time. As a result of her allergies, she is limited in the duties she can do in the clinic and as a result will likely never advance there. Maybe you could do reptile (turtle) and bird rehab since they have a tendency not to affect those with allergies.