The past few days, my Roku has been having issues with loading/streaming shows, and staying connected to my internet. No other device has problems with our internet, like Roku is having. Is there an update or something that I need to do? It isn’t that old of a device, I’ve only had it for less than 3 years
Settings > System > System update will show you when your Roku was last updated.
Settings > System > About will show you your Roku software version.
I've never had a slowdown like you describe but I HAVE had my download speed go to zero even though all my other devices had no problems. Here's what has worked for me to recover. It's a mixed bag as to whether it helped others - I guess this means there can be several different causes of the symptoms.
1) Restart your router, even though other devices connect to it without problems.
2) Restart your Roku via Settings > System > System restart.
3) Set up your network again via System > Network > Set up connection