"We missed you hissed the lovecats"

Today I had to bring my Nan's cat to the vet and the vet told me that the cat needs to be put down as she is very old and she is in a lot of pain as she was hit by a car. I am distraught and cannot stop crying. I do not know what to do as she is my Nan's companion. I am going to take the cat back to my nan so my nan can say goodbye. This is a really horrible day.