This is not an Inkscape issue per-se but I am wondering if anyone else has expericenced this.

Somehow all my Inkscape files got switched to .psd extensions and I can no longer open them with Inkscape. I have a feeling it has something to do with Google Drive

I get the following error:

Failed to load the requested file C:\Users\joe\Google Drive\KW\Marketing\Business Cards\back.svg

Has anyone encountered this and is there a way to reverse it? I have no access to any of my files anymore

I don't know how it could have just happened, but try opening one of the files in a text editor. If it looks like an Inkscape SVG file (i.e. the editor opens it, but there are lots of < and > characters, and mentions of svg, inkscape and sodipodi in it) you should be able to just rename them back to *.svg. If they don't look like that, then it would seem that an actual conversion has taken place, and you might need to post an example file here for further investigation.

I think it's definitely due to the googl drive. If I was you I would try opening with another image editing software and save it as an SVG. You dont have to use photoshop, I use some of these other pieces of software on top of using Incscape, exactly for moments like this. Once you save it as SVG from another software you should be able to easily open it with Incscape, let us know how it goes:)

Maybe your svg-s got assigned to be opened by photoshop by default and they got the ps icon instead of inlscape's.
By right clicking-open with probably you can still open them with inkscape and reassign the default program they are opened with.