Between going to the Dr's and WW - I guess you ate lunch right?
That 2lbs difference could be the lunch you ate or the water you drank... Don't feel bad, take one scale and stick with that - it's the difference in the readings on the same scale that counts - you're following the trends, not the numbers!
Personally I don't take any notice of the Dr's scales since I am usually wearing different clothes and have eaten different things before I go see them. I only register my weight first thing, starkers and "empty"