where does the time go?

I don't know why but I have the feeling that this week has passed by way faster than any other work week ever did. I haven't even noticed how Monday turned into Friday, but here we are facing Saturday already... Unbelievable... Where does the time go? Today me and my group had to work on the project for our advertising class.. Well, we planned it that way that we have four hours to do so. At the end we realized we haven't been able to accomplish anything. What is to blame? the easiest answer would be the lack of time but it probably isn't the major case here...