stevie I'm sorry to hear of your nasty experience, you've had some good advice here you should follow. Most of all accept that it has been a short time and you will come to terms with it. I agree with the 'thank goodness it wasn't worse' view.
Quite coincidentally I was also involved in a RTA on Tuesday night, stationary in a lonq queue on the M25 and some idiot smashed into the back of us at some speed. i was driving with 2 passengers and we were OK apart from sore necks and backs but I've also thought back to it a lot, it could have been far worse. The aftermath of all the phone calls, form filling and being chased by insurance companies to put in a personal injury claim didn't help either. Anyway I wish you all the best.