Oh Mary, I am SO sorry to hear about your loss!!

I know that pets are a huge part of our lives and you have my deepest sympathy!!
We lost our beloved springer spaniel, Ben nearly 2 years ago when he was 13 years old and it was SO hard to deal with! He had been battleing nasal cancer for about a year which the vet said was extradionary (Most only survive 3-6 months with it!) but one day, it got to the point where he couldn't walk and eat so we had to have him put to sleep. We all felt SOO bad and cried for weeks but thinking back, it was probably the best thing for him as he's no longer suffering.
When Ben died, we created a 'memory box'. We put in his favourite toys, collar, leash, brush etc. It was very hard to look at at first but does help now so that might be something you want to look into, when you feel up to it.
I know nothing I or anyone else says will help but just know that you are in my thoughts and prayers and if you ever need someone to talk to, I am here for you always!!! You did your best for Ernie and he was SO lucky to have you take such good care of him!!!
Take care hun and my deepest sympathies!