Your upvotte total for one of the questions was likely one more than what shows. So for one of your answers or questions you had four upvotes instead of three (for example). Then, someone downvoted that question or answer. So it would appear you have six upvotes, no downvotes but you actually had 7 and 1. Then the question in which you had an upvote (whether it was you who asked it or someone else who asked it with you answering) was likely hidden.
The other explanation is just a bunch of stuff getting hidden. One or two or even three questions/answers of yours with upvotes got hidden or the question they were on got hidden. Same with the downvote.
