M.M.
Most BC pills suppress ovulation. They don't stop you from making eggs.
Unless you know that for sure (having been tested to verify it), take a step back. You don't say how old you are, but things are wonky post baby, post pill.
Go see your GYN, and go through the regular series of tests. It may be something as simple as you not ovulating when you think you are. It may be something more complicated.
But no one out here can tell you that, and it's unlikely that the pill you were on "caused you not to be able to have kids anymore".
If that were true, I would have signed up for it years ago!