I updated and lost a metric ton of content

I had spent hours adding traps and thematic details to my dungeon. Many of them were to have important mechanical elements and narrative impact.  They were also memory aids for me about how I had adapted the dungeon. I ran the recent update and noticed how much faster everything was loading.... BECAUSE ITS ALL GONE.  To be fair, not everything is gone. But more elements than I can easily identify.  I am near tears. This has been literally 6-12 hours of work on 5 of the gargantuan DotMM maps. now it is broken in ways I need hours even to figure out. I have logged in and out a few times and will again, hoping it will somehow revert.

UPDATE!  They rolled me back and the issue was corrected. It may have also been that the system reset the background in front of what I had placed in the map. Regardless, its fixed. Thank you to the community and the support staff for the help.

Another possibility is having two game windows open at the same time. Roll20 can become confused over which one is "active" and fail to save some data.

Thanks Keith! This was a bit more than that (several weeks worth of work). but it was resolved. Not clear if the rollback solved it, or if the update just moved the maps in front of my work. Either way, its fixed now. As always, you are the absolute BEST.