2002 A6 3.0 85K miles.

My red oil can light comes on the display followed about a minute later with the blinking CEL so I pulled over into gas station parking lot. Opened the hood and checked the oil level and it seemed to have plenty of oil. I have been checking my oil regularly because I have a small oil leak so until I’m able to afford to get it fixed I’ve been changing the oil every 2,000 miles.

The car will turn over but won't start. It never ran hot and the oil temp never got overheated.

 

Whitish foamy isn't standard issue fluid, but if the crankcase is overfilled, the crank will whip the oil into froth which will not hold oil pressure, maybe you overfilled and it found its way out of the engine? As for not starting, that is strange. I would have someone have a look at it, checking compression first. You also might have broken an oil pump chain, although that would be very uncommon.