Everyone has these days. Moms rarely get a day off and it never helps when you're feeling like crap. I've had the same kind of mornings with my kids and felt horrible about it. Later on, I made a point of apologizing, giving hugs, and just explaining that I wasn't feeling good. Kids quickly forget outbursts. It's a good opportunity to set an example in saying "sorry, I messed up".
Keep your chin up!