Soaking your feet in hot water will often relieve the pressure in your head. Also, on the fast, we are able to use essential oils and things like cold compresses on your head would help. There are pressure points on your hands, and ears you can press to stimulate relief. Look on the net for accupressure points for headache relief and other info if need be like the oils.
I also want to assure you that this is a normal detoxing reaction and that with time, water/lemonade, and patience, this too shall pass. Often just laying in dark quiet room away from all stimuli will bring relief since you are releasing and this is a good sign of your fast doing what it is supposed to do. Different days will be like this and is the *low* Somer often describes. Keep up the good work.