Recently my alternator warning light on my 2003 A3 8l 1.8 came on. After a few minutes of driving with this light on I pulled over and turned the car off and on again. The light was still on but when I tried to drive away there was no power. I could rev the car fine but when I tried to drive it would bog down. Can a faulty alternator put the car into limp mode? Any help is greatly appreciated

Thanks