Loose dog. Depressed.

I'm very depressed and worried about a loose dog we saw running around the condo. We saw him twice but couldn't stop for a couple of reasons. (On a rush to an important appointment, our yorkie/silky is dog aggressive and my son is now very scared of dogs thanks to three loose dogs who chased and nipped him.) After we got my son to school we tried looking for him and even drove to the home we think he came from but couldn't find him.

I talked to our neighbor today and she said she called the number on his collar but couldn't prevent him from running off. The person answering said it wasn't their dog. So now I'm sitting here watching Craigslist and hoping to see someone grabbed him.

I'm very upset, feeling guilty and depressed over this. Next time I'll make my dad stop :-/