It is my experience that around this time you NaNo writers have either reached an exulting point of no return or a pit of desperation.
To those running along quietly and are on track I say good job. Keep going. But this message is more for the people who at this time, at just over one third, only see desperation.
Hold on. Your work is not crap, you have just lost track of it because concentration and excitement for starting something new can only last you so long. Remember that after you have written there will be editing in which you can throw away anything you don’t like, but if you throw it away now or even quit, you will have nothing to edit.
Let what you don’t like be, make a sideline remark reminding yourself what you felt here, and keep going.
Possibly it is time for you to change things up a little. Throw in something unexpected if you haven’t already done so because if I know readers, then they love a plot-twist. Is the enemy you have right now really the enemy, or have they been set up to look like it? Is the friend really a friend or does he/she give funny looks that you can edit in later so that this plot twist will have a ramp to land on?
Just don’t stop. Even if you take a time out and fill a page with your current emotions and thoughts on how everything you have written SUCKS (I did that last year and it helped lots), after that get back to it. You as a person are unique and therefore only you can write this story. Give this story a chance.