[GianFabien]

I did what you are doing for just over 2 years. The burnout got to the point where I quit my full-time job and tried to make my side-project the only project. That didn't work out either. Ended up doing a form of detox (work can become an addiction).

When we're young, we do stupid and self-destructive things. But working more than 60 hours a week for years creates dire health problems. The human body and mind is not capable of 100+ hours work on a sustainable basis.

Based on my experiences, I would suggest you take time-out, reassess your priorities and craft a healthier future.

BTW in many jurisdictions your full-time employer can make claims on the work you do on side-projects, especially if it contains intellectual property that is related to the work you do in your full-time job. I personally know at least 2 persons who got sued by their employer for that reason. That is additional stress that can break some people.