Coping With Feline Leukemia Virus

approx. 4 yrs. ago I found a black kitten. kept her indoors. Also had an indoor/outdoor older male cat. approx. 1 yr ago, he was severely bitten, and recovered. however, exactly one yr later he had to be euthanized due to age and illness (not related to bhe injury) 3 months later, I came home one night and clara’s eye was completely glazed over. I rushed her to the vet and blood was taken. the vet told me clara tested twice for feline leuk. I was devasted. the doctor said her condition was very painful and most people opt for euthanasia. reluctantly I did do this. I have not forgiven myself. I am constantly questioning my decision, did I act too quickly, etc. I havent been able to put this to rest. I feel like a complete failure and that I let Clara down.