My headlights work... sometimes?

My '02 Focus ZX5 has some sort of headlight issue that started the last couple days... noticed it coming home on Sunday, the headlights kind of did a quick flicker. I didn't think a whole lot of it, just thought I was seeing things.
Last night, I went to go out and neither one of my headlights would work. Running lights worked fine & high beams are fine. If I remember right that's because running lights are usually your high beams but not at full power?
Either way, my headlights will sometimes work, and other times will not. I could understand one side going out or something, because I noticed today one of the connectors is pretty much shot. I'm going to replace it this weekend, but I don't think one side connector would have anything to do with the other would it? Wouldn't it be some kind of safety thing so if one side goes you still have the other?
I was first thinking a fuse when they didn't work at all, but now that they sometimes work, maybe the switch? I'll look into it this weekend for sure, but just wondered if anyone else has any ideas?