Number 3 - no dice

With my two sons I conceived first month trying/not avoiding pregnancy. I was really fortunate and tbh took it totally for granted that it would just happen like that for us again.  Now that we have made the decision to try for a third and final child and no luck at all yet. 
First month timing was off as I just had the implant removed but I've been using OPK and tracking diligently since, and BDing according to high and peak fertility according to Clearblue. And nothing. This month I really thought it was our month as I had really positive signs post ovulation however I can feel those telltale cramps that definitely point to AF
I had an emergency section with my second due to a massive bleed owing to undiagnosed placenta praevia and I'm really worried something was damaged during the procedure.
Is anyone in the same boat of not having any success on conceiving after having one or more children?