midnight1s1s

I hope you all can help. I bought my 2011 Aveo a little less than a year ago for my mom. She has since got a different vehicle, so I took the car back. In that time, I've had several issues, the most recent one being the most concerning. About 3 months ago, I replaced the battery, and about 2 weeks later, the battery light and the brake light started coming on simultaneously. They go off on their own, and stay on for a few seconds to as long as a minute. Then, about a month ago, it progressed to the airbag indicator light coming on at random - in addition to the other lights. I've also noticed that the engine runs rougher when this happens, and the AC fan doesn't blow as cold or as fast. Then, over the last 2 weeks, all of the lights have continued coming on, only now, my RPM, Temp, and Fuel gauges all go down to 0. Tonight, all of the above happened, and my turn signals started making a funky buzzing sound when they were on.

I still have a loan on this car, but I'm really concerned that it will progress to a point where the brakes won't engage when I'm driving. Can someone please tell me what might be going on?