Your In a dungeon for a damn long time I say It needs a sleep skill. though the only one skill I can think off Is a sleep deprived skill that gives you more health when you eat food >.>
Well, the game does effectively have a 'rest' skill, but it's just skipping turns and letting natural regeneration take over. And 'Digest' could even be considered a type of sleep mode, since functionally(Being immobile for a large number of turns, unless combat starts) would, I think, be almost identical.
Check out the Chronomancy mod. The first level is called "Daydream" and does exactly what you're asking for. It makes turns pass, and gives you random amounts of hp and mp while you rest.
