But see, that's part of learning. My explanation for those who may not know: Companion tanks are terrible, except for Treek. If you don't want to use Treek, then you probably would want to tank yourself in a dps mode, and have a healing companion. As a Sorc, you have some good defensive abilities. Also, learn which commanders are easier than others if you're not doing the "kill all 8" achievment. Finally, know how to use a rotation. Dulfy's is good for that. Don't hesitate to use Heroic Moment either, and all of the abilities if you have them. If nothing else, it shortens the fight.
There is homework needed sometimes if you want to turn hard encounters into more manageable ones. If you go in blind, then yes, you'll have difficulties.