I seem to have one everyday, sometimes I wake up with it and it lasts until I go to sleep at night and does not shift even after a nap. Should I be concerned? Does this mean i'm not drinking enough fluids? I take a litre bottle to work full of water and re fill it up at work and then a few glasses of water when I get home. Also, i've noticed when I have a bad migraine I have bad nausea. Can someone help me.