Hmmm i'm going into rehab on the 10th May, it has meant a load of hassle and moving a mountain to ensure that when i come out i will have my cat back...otherwise i would not go in. Her name is Trixie and i would rather gut a human being than lose her, i will be leaving her with a good friend of mine who has 3 years sober through AA. The same person had a cat for 16 years whilst drinking, so i believe she is in safe hands.
I think you are in a difficult situation and i do believe that you have to do what is best for you...