You need to make sure that you also take the node that makes DoT ailments apply on force shield instead of health, otherwise you can't survive any DoT.

If you don't have this node, you can try rotating the wheels so that Masochistic Effigy remain inactive. If you can't reach the other node or don't want to go there, I'm afraid the only thing to do is to reset your passives.

Edit: It's called Resilience to Corruption in the Warlock tree. You may also be interested in the Faith Leech node in the same tree that allows life leech to be applied on force shield, otherwise all your life leech becomes useless.

It's called masochistic for a reason, but I guess you missed the que? Even if you could get 350-400k force shield (this might be doable with max force shield mods on every piece), it's still worse than 1/5th that HP amount, with good resists, and you need to get extra mods on the passive tree to make it function as effectively as HP.