Karen -
Just a thought here - I am ALWAYS up a bit the day of and the morning/afternoon after I work out hard like you said you did.  I had someone (one of the infamous "they", I suppose) say that the muscles are requiring more oxygen and water to promote the healing process and therefore we gain "weight"  I lost a large amount of weight at a center that was right next door in a small plaza to a women's gym.  The women would come in to the WLCenter, weigh, go next door, work out, and come back in and weigh.  They would be up anywhere from 1-3 pounds.
No advice for the pooper 
 
  
 
Chin up, baby!  
