2000 Chevy Impala lights

Electrical problem
2000 Chevy Impala V6 Front Wheel Drive Automatic 105000 miles

When I turn my headlights to bright, after just a couple minutes, all my lights go out. Then I switch my brights off and my lights usually come back on. There were a few times when the lights did not come on for a few minutes. I think it was raining when they would not come back on right away. It has been doing this for about 40,000 miles.