I was wondering if I could regain ownership of the following post from last week.
Here's a post from Meta Stack Overflow that addresses it: Is there a way to remove community wiki status?
Here's the relevant snippet from the answer to that question (by Jeff Atwood)
Yes—community moderators, at their discretion, can now remove community wiki status from particular posts.
(blurb explaining when posts are automatically made community wiki)
However, if you feel your post has been unfairly converted to community wiki and deserves special treatment, you can flag it for moderator attention and plead your case to a community moderator.