I'm working on a game in Pico-8 but it won't load my file dispite saying that it saved (I'm on Windows 10).

Type folder in the PICO-8 console to bring up the PICO-8 folder. Click on the carts folder. Is your game there? If you have it elsewhere drop it in the carts folder and try load mygame again.

Me and my dad managed to figure out the issue, Pico-8 saved in the wrong profile's folder.

You can alter the save path in the config file