I don't see where the whiny little **** part comes in. You have something big bothering you and you don't know what to do about it. You get to ***** about things like that... but then you have to start working on finding out what's wrong and how to fix it. When was the last time you had a vacation or had some fun?
Any chance of you getting some counseling/therapy to find out what's going on?
I think anyone would have reacted to the dog snapping at your child even if the dog is yours. That isn't good.
Hang in there and take care. You can figure this out.