2012 Comfort setting, NO HEAT

Well, it's been almost 6 years, and I've never had an issue with getting heat when I want it. I'm used to barely getting warm air in ECO, but today I had it in COMFORT and HI, and still the heat wouldn't come on.
So I did a remote start a couple minutes before leaving, but not long enough to really warm it up. When I got in, the air was slightly warm. Just after leaving my driveway, the thermometer dropped to 22F, so ERDTT kicked in. It heated up quick and provided nice warm air for about 5 minutes after the engine stopped. I kept it in COMFORT 76F for a while, and the air started getting cooler. I turned the temp up to no avail. I'm fighting a bit of an illness, so the cold was bothering me and I was getting frustrated. The engine never kicked back on either (and no HOLD).

Finally I stopped at a stoplight and shut the car down and restarted. When it came back on, the temp read 28F and the heat kicked on instantly. I had warm air in under a minute.