Look. Speaking from experience as a police officer myself, he was only nice to you because he thought he might be coming up on murder charges or at least vehicular manslaughter if the POS had managed to pull down an okay public defender. This guy will get nothing less than he deserves for what he did. Also, you were going the speed limit at the point of impact, right?

This guy is 100% at fault here, don't try to blame yourself at all. Also, let the police traffic accident investigators determine speeds of the vehicles involved. I applaud you for your sincerity and honesty, but this guy MUST be removed from the streets. There is no doubt in my mind that he's got at least one prior for DUI and actually done it more times than dollars in my bank account right now without getting caught (and I just got paid w/ overtime).
Also, to anyone else. When involved in anything but a small fender bender in a parking lot, ALWAYS go to the hospital unless medical personnel on scene state that you don't need to. When involved in something like this, your body released tons of adrenaline and endorphines to "prepare itself" for what happened. Because of this, often times you can't feel any pain from the majority of your injuries. You WILL hurt tomorrow and probably more the day after that. If you notice any bruising, from the safety belt or any other areas, have someone photograph it for record. You never know how your skeletal system has been jolted and the long term effects of it. I'm not telling you to find an ambulance chasing lawyer or anything else, but this stuff can be serious. Hope you feel better and stop worrying about the perpetrator. He's gonna get exactly what he deserves from this.
EDIT: with the photos, make sure you can date/timestamp the photos directly. If not, and you're using a disposable or standard film camera, make sure that you take them same day to get developed and keep the receipt for processing for your record to maintain a good time record.