Warning lights after driving with e-brake

I have a 2004 Prius that is mostly my girlfriend's car. She never uses the emergency brake, but I'm a compulsive user of e-brakes, so this might be my fault. I drove it last night, and this morning she used it to take the cat to the vet. When she came back, she said it was running funny at first -- no power, slowed down drastically as soon as she let off the accelerator, etc., and that there were all kinds of warning lights. She said she pulled over and put the e-brake on and off, and after that the car ran OK but the warning lights were still on. My best guess is that the e-brake was on the whole time until she pulled over, and that was the cause of all the problems. From the symptoms she describes, it makes sense to me -- except for the warning lights.

She drove less than 10 miles. The lights that are on are the big red triangle, the check-engine light, a yellow exclamation point, and one on the screen display that looks like a pinkish silhouette of a car with an exclamation point superimposed on it. (See pictures below.) I can't get it looked at by my mechanic until next week. I'm tempted to just unplug the battery overnight to re-set the lights, but then if it wasn't the e-brake, I'll be out of luck on finding out the real issue.

Does anybody have any experience with this? The car was running fine until today. It's got a little over 120,000 miles on it, and I put in a new 12-volt battery about two years ago.