Bike accidents should generally be handled just like auto accidents. Get names, insurance info, etc. If you think you might be injured, call 911. Depending on your state and local requirements, you may need to involve the police for all accidents or just those above a certain property damage threshold or in the event of injury.

Do not apologize, do not say you're ok, do not admit any fault. If you do any of these things, the other guy's insurance company may take advantage of that.

In the case of dooring, it's usually the driver's fault (either legally or in an insurance liability sort of way). I could see an insurance company arguing counter, however, if you were traveling within a parking lane at the time.

The best bet: stay out of the door zone. Even if there's a door zone bike lane, recognize that it's just there to show you where NOT to ride. I hope you feel better and that it's nothing serious.