This thing you're goin through right now is normal!I just got over a similar "pit in the stomach"hopeless type attack the other day when I noticed a few more rough spots on my project.
I just remind myself that I can do this so long as I do it one step at a time and not try to build rome in a day.
What I recommend is to find some pics of some really sweet finished trucks and have a good look at them to help keep fresh in your mind why you are doing this.Try to break it down into small jobs and do your homework on each task before attempting it.Remember that this site is a gold mine of information and talent,we all are here to help each other!
Figure out what part of the build you are best at and enjoy most.When things aren't going good on one of the other phases,walk away from it for a little while and work on one of the other areas that you excel at.
Don't get too hung up on deadlines if at all possible either.I really believe that they are more harmful than helpful.I want mine done asap like anyone else,but I'm not gonna sacrifice quality or go into the poor house to meet a deadline ya know?
Don't give up,remember that whatever problems you are having with your project,someone else on the board is having the same or worse problems with theirs!
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'72 C-10 Proud owner of a million new and used pieces that used to be and will once again be(god willing) a testament to the term "they don't build em like that anymore. 
'80 LWB 2wd beater
'67 GMC long fleet (cab donor)
'66 long step (parked till it's turn comes around)
'65 short step (parts truck that will donate it's bed and possibly frame to the '66)
'06 Grand Prix wife's car (she hardly lets me touch it)
my pics