My missus claimed: genuine whiplash as a passenger in a vehicle that was shunted by something accelerating up behind them as they waited to enter a busy roundabout. It affected her for months and months.
One thing that I always think about when I hear these discussions that I wonder if people bear in mind.
If needs must (like my missus) fine, but just for those folks out there that try for an non-genuine one-off chancer. If you’ve had a payout on something like whiplash there is a chance that any kind of life/medical insurance you may want in the future you won’t [easily] be covered on spinal issues due to pre-existing condition that you WILL have had medically recorded for your accident.
As others have said give it a few days at least and see how you feel physically and psychologically.