Thank you all so much, especially all of you from the Creating the Hive community, for your kind and encouraging words. I think I've almost put this situation behind me (and a few others I didn't tell you about!), and your advice to deal with it then shake it off really helped confirm my instincts.
And I got to thinking about putting things into perspective, to really focus on realistically prioritizing the important tasks and figuring out where I can/should let things slide. At the same time, I came across this helpful article on procrastination and stress (by the way, if you're not familiar with http://www.smartbrief.com/, I would highly recommend their daily newsletters on topics like leadership, your career, and social media). There is a lot to be said for just waiting, a bit, to see what's really going to need your attention and what's going to take care of itself without your having to drop everything.
So, I haven't gone totally slacker, but I did sit down in a quiet room with a cup of tea, a piece of paper, and a pen. I folded the paper in half, length-wise, and started to list on one side the things that I felt were priorities, the stuff that just has to get done. I'd flip over to the other side when I thought of listing something that would be nice to do, but wasn't urgent or really necessary. Once I'd emptied my brain, I just sat and drank some tea, breathing deeply. Then, I went back to the list to start scheduling some dates by which I hoped to accomplish some of the listed tasks, not to create hard-and-fast deadlines or to stress myself out, but to sketch out if these tasks and timelines are realistic and to confirm that everything really does belong on the priority side of the page. All of this didn't even take that long, but I sure felt better afterwards. I did this a couple of days ago, and, a few times a day since, I have looked at that list to see if I can check a task or two off or if I need to modify the timeline. Of course, as old things get done and checked off, new items get added to the list, but at least you're not trying to keep all of it in your head! I hope this is helpful, and I'd love to hear about any systems you are using.