I'm not even gonna sit here and lie to you.
I do the same thing. But see I dont let the number I see bother me. If its lower hooray thats great but if it is a little higher I just know that I need to work a little harder thats all. We all have our off days and all the scale does is show us that in a number.
But if you do feel it's absolutely necessary to weigh everyday just do it in the morning not at night. By the night time comes around your full of water, your body may be heavier from your muscles being swollen if you had been working out, and your stomach has food in it.
Just dont let it get to the point where the number you see on the scale controls you. It should be about how you FEEL and how you feel about the way you LOOK.

http://myspace.com/dominiquecarroll
First Mini Goal: 265lbs-MET 8/24/08
Second Mini Goal: 245lbs MET 10/3/08
Third Mini Goal:225lbs
Goal:180-200lbs
Highest weight: 291 8/5/07 I lost 25 pounds on my own.
SW: 266
8/22/08- 266 Started Phen

8/29/08- 260 Down 6lbs
9/05/08- 256 Down 10lbs
9/12/08- 253 Down 13lbs
9/19/08- 250 Down 16lbs
9/26/08- 248 Down 18lbs
10/3/08- 245 Down 21lbs