Dropping

I'm having the same issue for the past 2 weeks.  And now it is dropping every night around 9pm, modem loses connection for a minute or 2, reconnects for a minute then drops again over and over till finally going down completely.  Always have to unplug the router only to have it start acting up almost immediately.  I also do not have cable boxes, but use the xfinity app and a roku to watch my cable, so not only do I lose internet, I lose tv as well.