Could be you have been putting on some muscle. That weighs more than fat. But I
don't think you would put on 2-6 pounds of muscle in a week. Wish I could.
Could be you have hit a plateau on weight loss that just happened to be at the same
time that you started exercising.
Don't stop the exercising. That isn't the problem...guaranteed. Give it a little
more time to kick in. You're down to a point that a little extra walking and at a
bit faster pace probably would be ok. You doing this workout program under
guidance of a trainer?
And, by the way, congratulations.
It's all about sugar, and hormones. It works.