Self-Sabotage

There are times when I wonder if I sabotage my own efforts.  I have been feeling very BLAH this week.  The wind is gone out my motivation sails :-(  This happens every time.  I have had good weight loss, I have not plateaued, but I don't seem to have the will power to keep going.  Part of me really wants this, and big part of me... but there is a small part (must be a strong small part) that just wants to keep eating what ever.  That is easy; that is pleasing to that small part.  I don't know why this happens and I don't know how to break this cycle.  I had committed to doing really well for the length of The Biggest Loser, but I don't even seem to have what it takes.  Really, I call that pathetic.  I know why I want to lose weight; I know why it is sooo important for me to be healthy.  But I don't know...