I think it depends on your build and level. For a level 15 pure psi-caster with minor minmaxing and wearing psi-beetle shell tactical armor (80 - 90 components quality), everything was a breeze until the last fight against Carnifex. I think I lost every initiative roll, but I never had to reload or plan ahead.
Carnifex kicked my ass, then I quickly and lazily crafted riot armor and a low-low shield emitter, and then he kicked my ass again, but slower. I think Carnifex probably requires serious planning ahead for most builds. Also, I didn't turn my shield on for most of the battles, though it would help, and is necessary for the Carny fight.
Anyway, my suggestions would be to wait until level 15 or so, and like Zetor said, turn your shield on before the fight if you're having trouble. And if you walk outside I think Gary (in the robe) will give you advice for all of the fights, so that might cover your first complaint. And Carnifex might be better to save until level 20.