I had the same problems. Until I was kinda forced to do a lot of work in my free time. Well I had to decide, walk away and let three other people down or just do it. That was the start of a couple of month where I worked every sunday for 8 hours on the project. For other people this is maybe easy, for me it was huge.

And the best part was it affected everything else. I started just getting things done I wanted to accomplish.

I did also some reading about willpower, how it works in our brain and how we can train it. It's a really fascinating topic and helped me alot.