Low HP/resistances

Im just getting back into this game and i have a lvl 60 assassin at act 8 and im getting 1 shot quite a bit. My HP is 1.3k and my resistances are pretty low. Is it better to get more health and resists from the passive tree or just use the crafting bench? My damage isnt an issue as i go thru mobs like nothing but the random deaths are kinda making me think my character is weak.