L68 CW on PS4 - What am I doing wrong?

So I just hit L68 with my CW. Have gear score of about 1600 or so with random greens and a few blues. Have the Lantern artifact plus one other. Have the free blue tiger mount from the PS4 promotion and the default noob healer guy at max rank (20 I think).

My problem? Everything kills me. I just don't deal enough damage to even handle minor mobs. I see other characters running about maps dealing massive DPS and taking almost no damage. My noob healer does an okay job of keeping me alive but a lot of the time the incoming damage outweighs the outgoing damage. What could cause this?

I didn't really follow a 'build' as such - just put the boons and feats on as they sounded cool and interesting. Am I using the wrong spells/powers? I rotate between icy ground, shield, desintegrate and slow time.

Would respeccing my character following one of the (many) DPS builds help? Should I be looking for particular gear in the AH with particular stats to keep me alive? I'm pretty stuck as most of the quests - even lower level quests - are just too difficult for me at the moment. I'm clearly doing something wrong!