The IAC was the first thing that jumped into my mind too, but I also would emphasize that the first step should be to check for stored fault codes.
VDC's point about the CEL not being indicative of oil lebvel was a good one.
I'd like to add that the oil light is not there to tell you the oil is low either. It's there to tell you that the oil is SO low that the engine has lost its oil pressure...and your engine is now in "phase two.... self destruction imminent) mode. Your dipstick is there to tell yo the oil is low and needs to have more added BEFORE it gets to "phase two... self destruction mminent". Check your dipstick regularly. I do.
I congratulate you on pulling over, shutting down, and checking the only thing you knew to check. If something catastrophic does happen, this action will save your engine. You did the right thing.