I called in fatigued last year before I even checked in for my trip because I didn't sleep well due to sick kids. Absolutely no push back. The duty pilot just told me to fill out the report and the company would determine if I would be paid out of my sick bank. He was very understanding and gave me no problems. Fatigued is fatigued no matter what the cause. You or 100% pay protected even if it has to come out of your sick bank. Never feel like you have to fly fatigued.