I used to have 91 rep on Area 51, 51 start rep + 40. This is what's shown in the
/reputations page, and the items in my profile also add up to 40. But Area 51 now shows I have only 27 rep (which means I can't even comment).
Your account was the target of malicious down-voting. A single user used 3 accounts to issue 63 "not a good example" votes against you over a 2-day span. The unusual votes were automatically detected and deleted, so your reputation has returned to normal. The two sock puppet accounts were merged into the original one.