might sell my 71 dart.. need help

I too learned the hard way. I would buy every project car I could get my hands on cheap and then never bought any real parts for it. Get rid of the other cars, put that money into one. Keep your daily driver and forget the rest. The older you get, the more you realize this is the way to get things done.
I feel the same way, losing motivation sometimes. But when you get passed a few hurdles (like getting the quarters put on), the motivation kicks back in.