What did I get myself into?

So I told a friend at work I would make her this HUGE diaper cake. It is for her sister in law and there is a train theme. I have to finish it by tomorrow night. I got off work early today with every intention of coming home and getting it all done today. I am make a big cake and 4 small ones to make a "train". I have barely gotten the small ones made and I am worn out. That may be why I am sitting here and not working on it. I know I will finish it but there is so much more work to do on it. Why oh why do I procrastinate so much???