I have watched my reputation changes and understood every one, until today. I answered a question this morning, received 39 votes, but no reputation change at all from that answer. I thought I understood the reputation system pretty well, including the Community Wiki exception, and the daily cap, but I'm missing something today.
Your answer was marked "community wiki". Revision history showed it was set by you 18 hours ago (as of this writing).
The best explanation I can give is that you accidentally checked the "community wiki" checkbox when making the post.
I removed the CW status and turned it into a normal answer. Visit the reputation breakdown and use the button at the bottom of the page to trigger a reputation recalc. You should get your reputation back (up to the daily cap) at that point.