Has she been eating since you brought her home?  Its so critical to keep there digestive tract moving to avoid stasis.  Perhaps try giving her some of her favourite greens washed with a bit of water left on them to increase hydration and ensure she has a lot of hay.  You can also sprinkle hay with dried herbs to encourage her to eat more. My female gets very stressed at the vet and she will sulk for hours after.  I always notice her poops a smaller for a bit after too.  Stress poops I call them.   If you still don’t see any new poops  I would give your vet a call.  Always better to be on the safe side.

How is she doing now?

If she has not pooped or eaten in 12 hours, please contact a rabbit-savvy vet and have her seen as soon as possible — regardless of the cause, going that long without GI movement is very dangerous and is a health emergency for a rabbit.

Vet visits and car rides can be stressful for rabbits. That being said, we do expect them to bounce back within a couple hours of returning to their space. If she is eating/pooping again at this time, in the future, you can consider preparing treats for her upon return, refreshing her litterbox so it’s nice and enticing for her to eat, and whatever else you think might encourage her to have some “pep in her step” per say. Some rabbits do like being left alone as they settle and try and feel more secure; however, we do want to monitor that that lack of movement doesn’t progress into GI stasis risk: https://wabbitwiki.com/wiki/Gastrointestinal_stasis