You've had a really poor response from the HN community here. Barely a single comment even attempts to speak to your question! HN is normally pretty good at resisting Sturgeon's Law, but not today.

muzani isn't asking to be talked out of working more hours, everyone.

Anyway, my suggestion: it sounds like you work alone. Maybe try working with other people, for a day or two per week. (I don't know if that's compatible with your line of work, or if you'd consider taking on a different one.) The camaraderie may help you make a habit of it.

Also, a formal commitment to turn up each week is likely to work much better for you than a take-it-or-leave-it arrangement.