Feeling this loneliness in your own projects is very common. They are somehow a long distance race. If you like it, you will find motivation sooner or later. Obviously, the lack of a paycheck for your own project may discourage you. However, nobody says it would be easy. Take into account that only because is a personal project, it does not mean that you will not find the difficulties of a real project. Lack of motivation is one of them.

Something that I find encouraging in my personal projects is to stop for a while, take breath, and realize of how much I have accomplished so far. It is probable that a little voice in your head will say "there is still a lot to be done". And maybe it is true. However, I think that satisfaction must be found in the daily task, not in the final outcome :)