I feel ya, the only thing keeping me to this project is that I am building it in Java, and I am a Java developer professionally. I am able to create progress reliably and have the tools to get things done. However before this I must have atleast 20 projects that I forgot within a week.

My only tips is to work with tools you are comfortable with, and lower the scale down a lot! Like really a lot, you should have something that is playable within a week, else you'll lose motivation.