No, using your computer as the admin and playing the game in admin mode are two entirely separate things. If you haven't specifically chosen to run the game in admin mode then you almost certainly haven't been. There is no way of knowing for sure as it isn't recorded anywhere, but everything you've described so far is exactly what would be expected from having been in the wrong mode, data being messed up and in two different "times" simultaneously is classic admin mode related damage.
Please see the opening paragraph of the FAQ for information on it and how to put yourself in the correct mode permanently.
No, I'm not sure why it would suddenly have changed, it could be that using a different program in admin mode as you said you did could have impacted it somehow, although that would be unusual.
The following is from the TEW2016 FAQ on how to find your non-admin mode files and put them in the right place - it'll work for WMMA too, just change the folder names used accordingly. This is really the only thing I can suggest to try and get your data back to the way it was, although if you've been playing in non-admin mode all this time then I'm really not sure how many problems it will have created. You should give it a go and report back.
I was running the game outside of admin mode and now can't find my save games...
You will need to 'rescue' your save games from non-admin mode in order for them to work. The following method can be used (quoted from a user post):
You should be in admin mode all the time, but you should be able to move the save files from their current location in order to keep using them. Assuming you are using Windows 7, the files should be stored in a hidden folder called appdata. If you don't have hidden folders displayed, then appdata can be found by typing "C:\Users\USERNAME\AppData" into the Windows Explorer taskbar (or in your start menu), substituting USERNAME for, well, your username! Once in appdata, you should be able to find your save files by going into "Local\VirtualStore\Program Files (x86)\GDS\TEW2016\Databases\DATABASE NAME".
Copy the save folders from that location to your default GDS directory (within Program Files) and they should work perfectly. If you are struggling to locate the files within AppData, then another option would be to search the AppData folder for "TEW2016.mdb" (minus quotations). Once the results appear right-click on one of them and click Open File Location from the drop-down menu.