Ok that’s good.
There might be various reasons why this could be, one could be a download (for example updates for the operating system (OS)) that is running in the background. Such a download can take 1-3 hours. With your 5 mbps connection you get around 30 MegaBytes per minute. A modern OS update can easily be 1800 MB large, sometimes larger. While it’s downloading that in the background, your connection can be overloaded.
Another reason might be an issue with the router, I assume you already rebooted it?