Izzie! Congratulations on the new baby....that probably explains the dark circles: lack of good sleep???? Also, could your iron count be low?? A babysitter and iron pills or raisins would help with that!
Otherwise, as you found out, it's a matter of trying several thinks to find what is right for you. Depending on what you want to spend, Cle de Peau on the high end has a concealer that gets good reviews but it is $65! Bobbi Brown makes a CORRECTOR that is peach tinted and does a great job of neutralizing the discoloration. It is less expensive that CdP. I've experimented with just about all of them and these two are my best recommendations. Let us know what works for you!
There are several other threads here about Dark Circles that might be helpful to you also!