do mother cats miss their kittens
Your cat may be missing her kittens, but it's even more likely that she has come back into heat. Cats typically cycle every two weeks, and they tend to do a lot of calling or crying as you describe it. If she's truly missing the kittens, she may try to butt in on the other queen after she delivers. You'll need to watch closely to see how the second cat reacts and intervene if necessary. You might even want to try getting her mind off things by giving her a couple of new toys to play with.