It is as if she is nesting. She has become aggressive to our other dogs. She is crying all the time and will not eat

I would take her to the vet and ask them to check on her. Change in behavior was one of the huge red flags that something COULD be wrong when had our pup spayed a couple of months ago.

Is she on pain medication?

By nesting, do you mean piling up bedding, rooting around in it and seeming generally uncomfortable with how it 'feels' or staying still for any length of time?

Is she drinking about the same amount of water or does she seem to be thirstier than 'normal'? Is she urinating within her 'normal' range?