Abby's mom, I totally understand your anxiety. I think if I had another pet to care for I'd be feeling much the same. Its easier said than done, especially when its not you going through it (and I'm talking about myself, here), but unless your pup is similarly ill, you'll be okay. You need the time away and consider that you don't want to stress Angus out either. They pick up on your anxiety and you want him to be calm for your trip away. He will be there, happy to see you when you return, refreshed.
I'm sorry about your loss of Abby, for your family and for Angus.