Well thanks. I would do anything for them and it's nice to talk to someone that feels the same.I know the feeling. Everytime I hear a noise that could be him wheezing, I mute the tv and listen carefully to see if it's coming from him or when I come back home the first thing I check is his back paws color. If they are brown-ish, he chewed at them again!
You're a good mom too for Runt. He's lucky to have you. You'll figure it out I'm sure.