I fear you're right about the project being corrupt. It happened seemingly so abruptly and without provocation. When trying to make a new project I couldn't figure out how to import using the All Files browser (I couldn't even figure out how to access external drives from there).
ROUNDABOUT FIX: So I ended up clicking in the timeline of the corrupted project, cmd+A (select All), cmd+C (copy), and then opening a new project without closing the project (or Logic). At this point I have two projects open with the new one being the live one (the one "on top". In that timeline I hit cmd+V (paste) and everything from my previous (corrupt) project fell into place, including automations. Now, with both projects open, I opened a mixer window from each project open and put them side by side. Next I went to SETTING at the top of each channel in the OLD Mixer and chose COPY CHANNEL STRIP SETTING, then I went to that relative channel in the NEW mixer and chose PASTE CHANNEL STRIP SETTING from the SETTING menu of that channel. I did this for each channel. It got tricky with the bus sends which I had to do manually for each channel once I had all everything else pasted in. But at least each plug-in, level, EQ, and send transported to the new project in this process. Time-consuming but better than starting from scratch.