I have to say...at least you got an apology, even if she didn't ask about your injuries. Clearly you weren't hurt - at least from an observer's stand point. I have been in that situation more times than I care to count particularly on trails and I figure it is just part of sharing the road.
I am really, really sorry you got tripped up by the lab, but I suggest that you just chalk it up to experience and realize that not all dog walkers are as responsible as you are.
2.5 years, 45 pounds later... 128ish pounds