What's the rush? Doctors suggest waiting 4-6 weeks for a reason. You might feel fine but your body just went through major changes over the past 9 months. You should give it a chance to rest and heal completely.
I would wait until you check with your doctor at your 6 week check up. Better be safe than sorry..and since your down to your pre pregnancy weight just try to maintain it for now by eating healthy.
I'm 3 weeks pp, and at my 2 weeks check up my dr cleared me for light exercise. She said mainly walking at this point. There's no rush, your body is still healing from a big event, and trying to push it will just make it take longer to get back to before. Maybe try taking baby out in a stroller for a walk when its warm enough. :)