I'll keep this in mind in case this happens again. Thanks!Tak.
Make sure that your monitor cables are tight. Also, use a program like HWMonitor (or whatever the Linux equivalent is if you are using Linux - I think you are right?) and monitor the temperature of your graphics card. If it goes over 60C the card may shut down the screen to cool off. Radeon's are notorious for not running their fans fast enough when the fan is set to auto. You may have to set the fan manually in the Radeon control panel. I have mine set for 65% and it seems to do just nicely.
Try that and see what happens.