You did the right thing at the time.
I'm sure the volunteer went home feeling like she/he had been a tremendous help to you, and will probably appreciate some feedback tomorrow that you are OK and felt in safe enough hands to let go.
When you are ready, you can go back all smiles and hopeful, and know that the hole in your heart is less raw and ready to be filled once more.
God bless your family this Christmas, having been through this you'll know exactly when you are ready to move on.