Back on topic, one of the primary issues people are getting at is that there are a lot of one round "you're screwed" effects in this game, which make consistent healing a losing game. Now, maybe your DM is just constantly hitting you with 75% of your party's hitpoints in damage a round and staying there, but in most cases we'd expect to see some Save or Lose effects thrown in, along with the occasional "actually, that was 110% of your hitpoints that round." As such, just trying to get hitpoints back just won't cut it.
At the very least, consider some ablative minions to take some of these early hits for you. A solid Disguise check should be able to make undead minions (Animate Dread Warrior, perhaps?) look like your party to take that early 9th level spell barrage, leaving you free to counter attack. Contingencies area also a very good idea. Illusions might help as well. You need to get clear of the early attacks. Frankly, your DMs style sounds strange to me... if he can fire off multiple Disjunctions then the enemy clearly has 9th level spells. Why aren't they dropping some kill/maim spells on you, especially if you have no items and thus your saves are quite poor?
JaronK