The Last-Part-Of-The-Middle-Is- SOOO Hard!

Okay. I think we have a bunch of writers out there, so I'm asking this question of you.
 Yes, you.

 Don't think I'm talking to the person behind you.
 (Not that there is anyone, since you're on the computer... but, you know, figuratively.)

 What do you do when you've got the lion's share of the plot worked out, you've got most of the scenes written down. You even have the ending done.
 And you've got all those pesky links to link up... and you've been working on this project for SO Long, sweating over it to make it perfect.

 Your brain revolts and your interest plunges to unchartedly deep places in the black ocean...

 And now you just want to chuck the thing and take a long walk off a short pier?


 All you want to do is yell "HELLLLPPPPP!" at the top of your lungs and have some celestial being sweep in on golden wings, slap the manuscript together and say, "There. Done."

Red Line= Writing Ideal ~ Green Line= Reality I'm hitting the hard, gravel grade that comes before cresting the summit on mountain roads. Have you ever climbed a mountain road?  (Agony!)
 I have, and believe me, the stretch right before the top is when you're murderously thinking "Who's dumb idea was this? It's not worth it! I can't believe I let anybody talk me into this." And "....why don't I turn around and go home....?"

 That is also what happens in novel writing. But it is of course your own idea, and so you can't blame anyone else.

 So, here we are.
  We're past the halfway mark, and not yet to the finish, and that is always the hardest part!

  The very last gasp!
      (But it takes so loooong!)

 
 How do you handle that "last part of the middle is soo hard!" feeling? Do you have ways of combating?
 Tell me!

 I need HELLPPP.