There’s a small chance that your client was corrupted too (which you could fix by reinstalling that as well), but what you just described sounded like an issue I have at my college apartment. Did your internet connection or network hardware (router or on your computer) change when this issue started happening? My issue turned out to be that a USB network card I had was pretty crappy and was losing a lot of data resulting in it being redownloaded over and over, and that would bottleneck whenever I tried loading a ROBLOX game.
If your internet connection hasn’t changed any time soon, it could just be that your ISP is having issues in your area temporarily or ROBLOX is having another one of its spats due to server overload (good because there are so many players, but unfortunate that it causes issues). If the issue still persists after a couple of days, post back here and we can look into something else.