you have lost your lovely (and beloved) pet.
Cathie, it is very sad to lose a pet. You will feel intense grief with the loss of a pet so incredibly close to you. Although grief is very painful, it is normal to feel this grief.
I understand your feelings about maybe having "let go" a little earlier. Yet, you did this as you were able to do so. (So many of us "second guess" how we'd handled situations involving needing to have a pet put to "sleep." It's a tough call, in every situation.)
I am sure your beloved dog loves you and holds no hard feelings/resentments for anything you have done out of love for your pet.
Please allow yourself plenty of time to grieve and work through this recent tragic loss. This all takes a great deal of time. (I had lost a dog 4 years ago and it was very sad; it does get easier with time.)
Please try to recall how much love you have shared with your pet and strive to always love yourself as much as your pet has loved you!
Please let us know how you are doing when/if you feel led to do so?
You and yours are in my prayers.