That happens to all of us. Now pick yourself up, remind yourself of why you started the effort in the first place, and move on.
Any chance you can join a club, group, or class that envolves some activity? Sometime that can be a real help. Not only do you get your body moving, but there is a social aspect that many people find motivating. I think having fun while I am exercising is really important. Sure, sometimes in the middle of the class I am swearing under my breath (and sometimes not so much under my breath. Last week I dropped a couple of f-bombs trying to complete a workout - and I rarely swear like that out loud
As far as hitting the drive-thru... DON'T. I know easier said than done. Instead of telling yourself you "can't" eat fast food. Remind yourself that you "don't" eat fast food.
Keep your logs going, good, bad or indifferent. A couple of embarrassing days may help kick your butt into gear.
Now don't be a stranger. You have been pretty active on the forums in the past, we'd love to see you back!