The fix is usually to drop the distance in half to the router. For those that dispute this fix I have used this fix for over a decade and in fact back to the 90's when I wrote router code.
There's another before you move the router item. Try changing the channel the router is on.
in my small room i have a pc that is connected to the internet via wireless connection, i have a 2.4ghz and a 5ghz connection but i only use the 5ghz, my problem is that i have to keep my pc in one spot in my small room otherwise my internet drops from 8mb/s download to almost 400kb/s download, this can be as simple as moving it onto my desk rather than under and this issue takes place.
any help would be greatly appreciated thank you!