I can understand your frustration! I also had a stall in week 3.
It can be very discouraging.
All I can suggest is to up your water if you haven't already, make sure you're getting in all 5 MF meals, and eat the leanest and greenest on the list for your L/G meal. And make sure you're watcihng your condiments and salt, etc...
I would also consider that while starting an excersizing routine your body may slow wt loss, muscles may hold on to a bit of water, and your body is readjusting.
It WILL come off if you are on plan 100%. Don't get discouraged!!
You are doing GREAT so far!
Hang in there!
Meg
PS: I've found that the scale makes me NUTS and for my own sanity I only weigh in WEEKLY...