I’m very sorry to hear that, although I would not give up hope. What you are describing is very rare, and as long as I’ve been on this forum, I have never heard of a case where Obsidian does anything like this on its own accord. Unfortunately, there are possible other factors that may play a role.
To start, I would recommend looking at a thread like this for initial suggestions: All data missing from Obsidian. There are other threads with additional suggestions, but I wouldn’t do anything drastic before you give a more detailed description here and get advice from someone more knowledgeable than I am.
There are other possible causes of data loss relating to using certain cloud backup setups, but I doubt they could completely erase a vault. Personally, I use Obsidian Sync as well as somewhat regularly saving complete backups of all notes in my entire vault on at least one separate external drive. On these drives I keep one backup of the media folder within my vault, since it is large and it wouldn’t make sense having multiple backups, filling up the drive with duplicates. However, I would be lying if I said I didn’t have a duplicate saved on each drive. I’m a little paranoid though.
One thing to be aware of is the fact that if you regularly rename media files, you can end up with some extra files when copying and pasting into this folder. Some people use more technical versioning solutions, but for any odd snafu that may arise, I know I can rely on Obsidian Sync, which is very useful in this sense although I am mainly worried about notes when it comes to Sync. It is worth reading about. It has some good features, and there is no worry about issues. This is not to say that there aren’t other working options. It’s just important that the option you choose is said to work in the Obsidian Help:
Here is some text from this page,
Some cloud storage services, such as OneDrive, allow you to only download files when you use them and later remove them locally to free up space. Since the files are no longer available locally, Obsidian Sync believes they’ve been deleted and removes them from your remote vault.
To use Obsidian Sync together with Files On-Demand and similar features, make sure to configure the service to always keep the files on the device.
Hopefully the file recovery works for you! I am very sorry this happened to you. People here will surely help you troubleshoot, and if it is possible to recover your files, I am confident you will.
Anyways, in my opinion, it’s better to have two physical backups on external drives that stay disconnected from your computer during normal use. If your computer happens to have two hard drives, it doesn’t hurt to also keep a backup on there as well. This may sound like overkill, but I don’t believe it is.
If these suggestions don’t work, I would return here and provide a very detailed description of your setup.
Good luck! Keep us posted.