Working 12 hours a day, 6 days a week sounds hard. How did you manage?
I remember feeling stressed out and exhausted all the time, having to manage client expectations and still keep working on my product.
What I would do is that I would start work at 12 p.m. everyday, and work until 12 a.m. from Monday to Saturday. Then I would crash on Sunday, and repeat the cycle.
We did this from Dec 2012 till end of Apr 2013, until our product was bringing in at least consistently four-figures a month, and we drastically scaled back on client work.