How was I able to vote 41 times?
This usually happens when something you voted on was deleted. When the post is deleted, you get that vote back for the day, but the vote is still counted in those counts. So you'll have voted 40 times on undeleted posts that day, but still have cast 41 votes that day, because one of the posts was deleted.
As the other answer mentions, if you vote on a post and it's deleted before the end of the day, you get to cast another vote:
In an extreme case, you can get almost double the number of votes.