I wrote a Python library that was pretty popular at one time. I gave a talk on it at PyCon, at one point it was in the top 200 most downloaded packages on PyPI.
Since my employer told me I was no longer allowed to work on it at work, I have felt quite a lot of guilt about all but abandoning fixing bugs and reading the mailing list. I've been working on a "next generation" version, almost a rewrite, but I don't see a clear path for releasing it in a way that helps people still using the current version.
It may be self-serving, but I am really going to try to take this essay to heart, and not beat myself up everytime a weekend goes by that I don't spend working on my project.