Dude. ... 3lbs is AWESOME. When I was on LL, I'd get about 3lbs in the space of 3 WEEKS, not 7 days. So, really.
And to be honest - if your body is over exerting itself (i.e. doing more than it's used to) on a small calorie count (way less than it needs to even function if you were to lie down all day) - your body will slow down it's losses EVEN MORE because it's trying to retain every last morsel of energy.
So don't overdo it. You're only doing more damage than necessary. By overdoing the exercise your body will be borrowing the 'extra' energy from your muscles - so you're only damaging your lean tissue in the end. ...
So Patience. Your body is losing weight. Be patient with it, it's not a machine.