You need to get yourself some Chasm gear. The mag resist will help with some of the spells, but more importantly, it gives 250 each to Body and Strength for each piece. Getting a complete set of Chasm gear will push your health up a LOT. Another trick to use, is to stay back and let the pet tank. Mine can take a level 100 wizard, taking the nukes, and lose less than half his health. Of course, mine is using Chasm, so it will have a lot of health, but pets in general have lots more health than players.