@halseyst 

Connect your computer directly to the modem for at least a day to see if it still drops, if not swap the Ethernet cable, and update the firmware on the router.

You could also do a constant ping during the drop time to see if IP still works, if so then the DNS servers may be the cause.

@Tony I've tried being plugged into the modem and it still happens, firmware is at the latest version.

It's not a problem with the ISP because if I plug directly to the wall (my apartment manages the internet), it works, so it must be something at the router level