Building a car is very similar to building a house or other monumental project. If you look only at the whole project it very quickly can become overwelming and depressing. That is due to the seemingly small amount of progress that can sometimes seem to occur. I have been bulding on my 35 chevy with the 409 in it for about 10 years on and off,I understand your frustration, truely I do. But, do this, as was suggested above, make your self a list of what needs to be done, make each one of those points an achievable goal, and you will find that if you see these as completed goals, check them off the list, your frustration level will diminish greatly. Also do something everyday,even if it is just to go sit and think about what you should do next. Take heart in what you have done already and do not lose site of your ultimate goal.
GoodLuck and stay with it
Big Jim