My Cat 'Blueberry'

Is very sick, we had to rush her to the Vet's this evening, it does not look good. We are all so upset we have had her since our son was 5 years old and he is 17 now. She is part of our family... we are waiting for test results, but we have talked it over as a family, and none of us could stand to see her suffer or be in any major pain that would break our hearts so we feel if the news is bad we want to do what we feel is the best thing for Blueberry. This is such a difficult choice to make and lots of tears have been shed tonight.