2001 Honda Civic No headlights sligh rough idle

My headlights don't work but the parking lights and hi-beams work. The fuses and bulbs are good just wondering if its the headlight switch that quit working? Also the car acts like it wants to die when I turn on the radio or turn the fans on, would this mean my battery needs replacing, lastly the car has a bit of a rough idle when its just running with nothing else on what could possibly cause this, Any help would be appreciated I'm trying to get this car running smooth so I can get rid of it its caused me nothing but problems since I got it.