Never applied with Spain but have applied with France, Germany, UK and Italy and all of them were very fast. Now, France had a bit of a fit becuase they didnt want you to apply more than 3 months before your trip (I think it was 3) but they approved anyways. Maybe Spain is waiting a few days to make sure you are within a 3 month timeframe? I wouldnt worry too much as you haven heard, if there was a problem, they would have told you sooner I think. I think it is just because you have applied so soon and they are in no hurry.