You start off with 3 unlocks, and get an extra one every Friday, up to a limit of 2. So yes you probably have used all your unlocks for this week.

If you feel lucky you might want to contact the developers directly here, and they *may* give you another unlock:
http://www.lfs.net/?page=mailus

You should note that if you want to play on DEMO servers you don't have to lock LFS again (I'm only pointing this out as it's been a comment issue fairly recently).