Redfraggle....first thing to do is try and calm yourself down . I really feel for you, as I was having a hard time last week with DS being too demanding of me whenever I was dealing with Babyboo, but he seems much better this week.
Gosh, don't really know what to say to you, other than you're not alone and we are here for you to vent at.....
Have you been feeling like this for a while? Can you speak to anyone in your RL about it and do you think that this is maybe PND?
Maybe your DH is finding the transition for one to two difficult as well, and if he's tired and not functioning well at work it can be added stress on him too.
Can you get someone to look after your DD for a bit so you can get some rest when DS is sleeping?