[kmonster]

In some areas some additional monsters spawn when you reload the game, maybe that's why you got the impression of the game getting harder when you're killed.
To avoid getting hit try to get your AC as low as possible with armor, spells and other things, like your paladin's "protection from evil" special ability.
For some extremely hard battles you can turn down the difficulty to "very easy", but play at "normal" difficulty most of the time to avoid getting fewer XP.