No. She'll get over it in all probability. If she sits for a couple of hours and dreams of hatching chicks, then let her be.
What you want to avoid is her sitting full time.
Yes it would hurt putting some fake eggs in the nest for her.
She may just try to sit and hatch them and obviously they are not going to hatch and she will lose weight and not get the excercise she needs etc etc.
Whoa! This doesn't sound like a hen trying to lay an egg. This sounds more like a hen who wants to hatch eggs.
Lots of elderly hens who no longer lay eggs do this. Some keepers keep such hens especially for brooding and hatching.
I think what she wants is some eggs, not calcium citrate.