ETA: This info comes from a friend who is an Ob-Gyn, but I could have misunderstood her explination. :-)
Did your friend do IVF (embryo transfer) or IUI?
If she did embryo transfer, it might make sense to start feeling symptoms sooner (though 24 hours sounds fast), since the blastocysts are already several days old, and wouldn't need to "wait around" much before implanting, having already passed through those earlier stages of development.
i.e., If you had a 5-day transfer, you'd already be at 5DPO.
If the egg hasnt implanted yet.then you wouldnt be feeling pregnancy symptoms,since your body wouldnt be producing any pregnancy hormoen.I dont think its possible to feel symptoms within 24 hours.I wish.
We did IVF and i didnt feel any symptoms untill 6 weeks....