Jeremy,
The missing driving light should have no effect on your low beam headlights.
The first place to check for power to the headlights is in the LF electrical bay. If you have power there, check for power at the headlights themselves. You may have a bad switch, bad circuit breaker, bad connection, or just two bad blubs. I have seen two bad blubs many times. One blub can go bad and it is not noticed until the second one fails. Then a lot of people will not check the blub because they think that both blubs will not fail at the same time.
Gerald