Aw what a sad story It must have been awful seeing Angus lying in his own blood. But don't worry, you did the right thing. Now he is suffering no longer. He could've been suffereing alot and just didn't show it. Alot of animals will hide that they are in pain just because they don't want their owner to worry about them or have them put to sleep.

I think now Angus is running freely at the Rainbow Bridge with a big smile on his face