Barbarian is by NO means a defensive class so I would avoid choices that buff your AC. You have a scaling DR. That is very good and enough defense. You should strengthen your attack, cover your weaknesses (e.g. saves) and find tricks that increase your combat choices. I hate Superstition as a buffer but I loved it on my stupid barbarian. Keep in mind that you autosave against healing spells that would keep you alive when only your rage keeps you alive.

Did you take the feat that lets you rage unconscious as well as gives you another +2 Con in rage? It is very worth a feat slot.