OK I guess I'm in the minority on this one. But my impatience with getting my body back was really bad. I began ab work 4 days after I had Mason. In fairness, I started this at that point becuase I was having horrible back spasms day and night because of the lab of ab strength. I could barely walk upright. So I started back with planks on my knees and cunches (all with a scarf tied tightly around my waist) to begin getting ab strength back.
7 days after I had Mason I began working out again normally. I had to build cardio back up, so I started by just bumping my step height back up to 6". But I was doing Gym Styles for weight work and Drill Max, LIC, Low Max, Tae Bo, etc... right off the bat.
HOwever, I worked out until the week I had him, so I'm not sure if that made a difference with how ready I felt to jump back into it.
At any rate, I was careful with my form since my joints were still loose, and I pushed myself just a little harder everyday.
For me, I was in my pre-preg clothes by 2 weeks, the FIT

like normal at 3 weeks, belly was flat by again by 4, and the rest has been retoning ever since. Now, at 6 mos pp, I'm smaller than I was pre-preg by 2 pant sizes.
So, like others are saying, listen to your body. You know how hard you can push yourself, and when it's time to do it. Just be careful with your form, and make sure that you don't expect too much from yourself too soon. (I wish I'd followed that advice myself!)