I've been playing Nethack for a long time now, but I have realized that once I get down to Gehennom my maximum HP gradually decreases. I play as an elvish wizard, and I can not tell what lowers my hit points, but over time I will be like, level 25 and have maximum HP of 11. What keeps happening? Is it a life drain? My experience doesn't decrease though, only my max HP. Does this happen to you? How can I prevent it? Thanks :)