When I don't get enough sleep and start to drift off during the day, I get up and walk around to wake myself up. But when I do this, an erection normally follows. The other day at work this happened. But it was painful, like the head was going to explode or something. Eventually it went away, but I was a little sore after that and I think I could feel a little wetness. Has this happened to any of you? Also, I got sick later that day.