Game level keeps dropping.

The game keeps dropping level ups without dying. It has happened 3 time now. Once at level 18, 23, and 21. It happens when I get hit or attacked but don't die. Currently I was at level 23 and got on my horse and The horse jumped and I hit my head on the over hang, I didn't die but it knocked my level back down to 8. Another time I got hit by a skeleton again I did not die or come close but it knocked me back down to level 7.