It sounds like you might need a *real* break, like a hotel room by yourself sort of break. One where you get to be truly alone.
When you describe the breathing fast or wanting to run right out the door-- that sound to me like a momentary anxiety. You left, you came back to all this mess and demand for your attention--- the kids want you, the house is calling to you, the kids are not cooperating.... it's hard.
My girlfriends and I joke that it's almost worse when we leave, because we get relaxed and then ten seconds after we walk in the door, it feels like there's hell to pay for being gone. It also feels awful because there's just No Escape...
I don't know what to tell you it could be. Sometimes, I just have to take a lot of deep breaths and remember that this too shall pass. If you think it's hormonal, could they do some bloodwork and find out if you need some progesterone supplementation or estrogen? I know that has worked for some of my lady friends. One swore that she wouldn't have made it through her daughter's teen years without her progesterone cream (she adopted her daughter later in life!) .
I hope things improve for you!