I was laying in the bed about to take a nap and when i was falling into sleep my head started throbbing. Not like a headache but more like it was being squeezed tighter and tighter each time at a rate of maybe a couple of times per second. I felt like if it had gotten any tighter, it would start to hurt. Each time it throbbed i saw white flashes of light. I admit it scared me quite a bit and when I tried to get up, it was very hard to move. Finally i sat up and opened my eyes and my vision returned to normal (kinda hazy at 1st) but the throbbing continued for almost a minute as it slowed down and eventually stopped. I haven't done any energy work yet today and I havent tried to AP yet. Im jsut starting out and trying to get good at the energy work. Can anybody tell me why this happened and what does it mean?