You must have lost your connection and weren't aware of your opponent's move. Let me find a couple of links in the Help & Support section (bottom of the page, next to the green pawn)
https://support.chess.com/customer/portal/articles/1444849-why-did-the-clock-times-suddenly-change-the-clocks-seem-broken-
And
https://support.chess.com/customer/portal/articles/1444918-my-internet-connection-is-fine---why-am-i-getting-disconnects-
Always a good idea to do an occasional "page refresh" if your opponent hasn't moved in a while, just in case he moved and it didn't show up on your computer.
Hi! In my last game I had more then 8 minutes of time. My opponent don't play some minutes and the system tell me, that I am loss. What is it?