QoS causes slow download speeds

I am having problems with download speeds when I turn on QoS.  The speed drops from 65Mbps to 5mbps.  I use Direct Tv Now in the house and when someone is using it then speeds drop on my main computer, hence the reason for wanting to use QoS.  When I first started Direct Tv Now, last year, I set the QoS and everything was fine.  Now I just turn on QoS with no rules and the speed drops.  Also there does not seem to be a downstream QoS setting anymore, was this taken out by firmware?   Looking at screen shots I did in Jan 2017 there was a download QoS tab now it is gone.   Can I download a previous FW and reinstall it to get the QoS tab back?