After a brief look at the recently downvoted answers, I do not believe that what I'll say below applies to you in particular, but it does seem to be relevant to the question in general.
When I encounter a question or answer that I think is particularly bad, curiosity sometimes leads me to look at other posts by that same person. And sometimes many of those other posts are equally bad, which is not surprising because there are some people who are consistently thoughtless about what they post. Therefore I discover, in short order, several posts by a single user, all of which seem to merit a downvote.
On those occasions, I'm never sure what to do, because I don't want to be flagged as a serial downvoter. I sometimes compromise by downvoting only the two or three that seem most egregious.
The bottom line is that I do not think that a whole lot of downvotes in rapid succession, even if you could somehow know they all come from the same source, indicates that anything untoward has happened. Again, though, I don't think this explanation applies in your case.