Now_Or_Never
Yes the headaches are the worse, but I have to admit on my current fast, I have not had really bad headaches. I think it has a lot to do with your pre fast diet and habits.
When I did have headaches while fasting, I would get a cold rag and put on my head, and rest with a neck massager in bed. They have the cheap ones you just wrap around your neck, they are actually very soothing. Lie down in silence or a soothing melody playing, keep lights dim, even burn some soothing lavender or vanilla candles, wonderful, and try to think of what you are doing for your body and remind yourself this is only a moment in time, it will pass.
best of luck.