Well, I talked with the mechanic.

He said it was almost certainly a sensor issue because they had checked everything else out when they had the car apart. He reassured me (and I told him how much driving I was likely to do this weekend) that the car was safe and as long as I brought it in Monday, they'd check the sensors and clean them and probably the light would go out and stay out.

I am pretty well convinced this is a good mechanic - he seems to have almost more work than he can handle. And he was very careful at pointing out to me the different things he had done, and what was involved there, and he also insisted on going out for a fifteen-minute test drive with me to make sure that everything worked right.

So I'm going to trust him on this. If the worst happens, at least where I'm going this weekend, there will be other people from my university, so if the worst happens, I'll at least have a ride back home. (And I'll try not to think about what I'll do this coming Thursday. Maybe I can "hire" someone to drive me down and pick me up).

This is what I hate about being single and unattached and living far from family - how hard you have to plan for every last contingency. It's exhausting and I think it does make a person a little paranoid.