So sorry for your loss. Its hard to see the spark go out of them. Just hard.
For me, what I usually do is gather up photos and have a little memorial. When my horse died I wrote out the story of her life. Put it together with a few momentos and pictures.
I’m not a crying person, but little things can set me off. I had to clean up some junk out of my mom’s basement and found a nearly-empty tub of “bute” (a horse NSAID) thats was hers. I just sat right down and cried over expired aspirin that belonged to a horse that’s been dead 10 years now. Yup.
By the way, brief auditory hallucinations, or even brief visual ones are not uncommon. Like hearing a phantom mew or catching a glimpse out of the corner of your eye. Your brain’s just trying to sort it out, like, background processing.
If you feel like you’d like to talk about it, the ASPCA Pet Loss Hotline is (877) GRIEF-10.