My guess is that you reached the rep cap of 200 and then weren't able to receive anymore reputation etc (your 0 score for example)
However, if you had previously received an upvote (of 10 points) for an Answer that was removed (not downvoted, but removed) then it would take away from your 200 (e.g. 200 back to 190). If you have multiple answers on various votes and one of them lost an upvote it would be hard to tell that in fact it had gone backwards.
Regardless, you can always go to the reputation page to have it recalculated.