Yes, that could easily be the case.
Cats -- unlike dogs -- do not like to travel (e.g. in cars) and/or being relocated. When I moved to the new apartment, Bobby (still a catpup) spent the entire night in the litter box, and the senior citizen never fully acclimated. I was told this when I mentioned a "playdate" on Facebook, by one of my cat rescue org friends. Basically, a play date is a bad idea, and moving is fairly traumatic to a cat. So yeah, keep her isolated for at least another week, but even once you let her out, there will be an acclimatization period. Best to keep an especially watchful eye on her for the next couple days (and perhaps spend extra time with her), and in the first week or so when you let her out. Once she considers this her home, all will be well.