Little old man

Georgie is senior dog here in more ways than one. He's 13 years old and has been with us the longest. His vision and hearing aren't great, and he's lost a lot of the time. During the night he started wheezing very heavily, and I'm worried about lung problems or congestive heart failure. He's in his cage and I can hear him wheezing all over the house. I don't know what to do. Place an emergency call to the animal hospital? Wait until tomorrow (Monday) morning? I can't bear for him to suffer. I can't bear the thought of losing my little old man.