I'm going through kind of the same thing with one of our dogs. She's almost 17 so we knew her time was coming soon, but she is covered in lumps, her eyes are leaking something, her teeth are rotting, she's almost completely blind and deaf, and she can't jump on the bed or couch without help anymore. We will be putting her down soon. We took her to the vet a little while ago and he told us she isn't in any pain, but she's had a good run and I hate to see her like this.
I'm 20, so this dog has been in the family for as long as I can remember. It's not going to be the same without her.