Passing soft shelled or malformed eggs can be very hard for them and can make them feel pretty bad. Some rest and time hopefully will get her feeling better. I would do as suggested and supplement the calcium for a few more days, if low calcium was the issue that will help. Do you have oyster shell available all the time for them for calcium? Even though layer feed does contain calcium, needs from bird to bird can vary, and needs can vary seasonally also, some need more than others, having it available for those that need it is best. Keep an eye on her droppings and crop function. Do you know if she has molted this year? Hopefully it was just a glitch and she will recover, I asked about molt because sometimes after molt when they come back into lay glitches can happen until their bodies get it all worked out again. At 2 1/2 years old it's also possible that a reproductive problem is developing, but it's not necessarily the case, just something to be aware of. Hope she looks better soon.
Sorry for your loss 
