I had that same thing happen to me last year around this time, so I dismissed it as a "seasonal change", and like you I had some pain at the top of my head. It got pretty bad, so I went to the doc, and it ended up that I had a sinus infection and didn't even know it! The infection was due to the dry air, so with some antibiotics,and a humidifier, I was over it in a few days, and have been fine without nose bleeds ever since. If it keeps happening, you should see your doctor.