Blurting Out Negative Comments!

I've had problems in the past with speaking before thinking, but I think it is getting worse or maybe I am being hyper critical about it.  However, lately my comments are getting me "in trouble" with myself and others.  I'm fast to say no, or make a negative crack after someone makes a statement or asks a question.  This happens mostly at home with my sons and husband.  One thing I've noticed is that these comments often come out when I feel overwhelmed by my husband's arrival home after work and he'll have a 100 ideas or three things he NEEDS to tell me or he's mad at the boys for leaving tools out or not mowing the grass.  I really don't want to hear it and out will come the comment.  Lately I've noticed this happening during afternoon meetings-I'll blurt out a comment and then you can see me subtly covering my mouth with my hand.  I'm tired of hearing my voice come out in a negative way.  I'd like to change this habit.