Edit: Last night, I used the "Fix MergeList problems" option in the maintenance tab of software sources and at least for now, it seems to be working. So I probably wont need help with this anymore, hopefully.
Every hour or two, the Update Manager keeps giving me an error message saying that my APT configuration is corrupt and that I should switch to another Linux Mint mirror. It usually goes away when I do a manual refresh but it just keeps coming back. I have also tried switching to a different mirror but I get the same error. It also tells me to run apt-get update but even if I add "sudo" it just gives me an error message saying to run apt-get update.
It happened again so I'm adding screenshots in case they help. The first is the initial error, then it's the error I get when I try to change the repository and the third is the error I get when I try running the command it suggested:
Before you start trying to figure out which ram stick or ssd is bad, run “apt clean”. That clears the cache that it’s saying is all fucked up.
Right now it seems to be working fine, so I'll try that later if I have issues again. Last night, I used the "Fix MergeList problems" option in the maintenance tab of software sources and that seems to have fixed it.