active and aggravated

My body is being typically stubborn. I've gone from frustrated to disappointed to angry. So far this week, my activities are the usual:

Sunday = elliptical machine, 25 min. (400 cal)
Monday = very brisk walking, 30 min. (150 cal?)
Tuesday = elliptical machine, 25 min. (400 cal)
Wednesday = very brisk walking, 30 min. (150 cal?)
Thursday = elliptical machine, 25 min. (400 cal)

Somehow, between 11:00pm Tuesday night and 7:00am Wednesday morning, I gained three pounds. Where the hell does it come from? I realize that PMS-related hormone changes cause water retention, but COME ON! Three pounds overnight? This isn't fair!!! It's beyond comprehension. I'm working so hard, and I have nothing to show for it. And I want to cry, and that makes me mad too. Argh.