Should healing be this difficult while leveling?

[Lyrica_Ashtine]

For starters, how much HP did the tank have? That would give us an indication of the estimated item level. How well equipped are you yourself? In particular the weapon comes in mind. Were any cooldowns used? Did the warrior hop into Deliverance at the very start or only for the last bit? Did he dodge AoEs?

Aside from that here are some general ideas:
Holy is a pseudo Hallowed Ground; You can stun groups for 7 seconds total. Just use Tetragrammaton or Benediction in between or after if you're worried
Don't be shy to use Benediction. Benediction that is always off CD doesn't heal at all.
Use assize whenever. You could wait a few seconds with it if there are the right reasons for it (like one lily away from the last one)
Don't forget about Thin Air. Ideally you'd want to use it for expensive spells like Holy, but if you're that starved for MP, you could squeeze out extra spells out of "thin air" like that
Are you using your entire kit? From my own experience I noticed that healers tend to forget about Asylum, Presence of Mind, and Benediction

[Renryuu]

For starters, how much HP did the tank have? That would give us an indication of the estimated item level. How well equipped are you yourself? In particular the weapon comes in mind. Were any cooldowns used? Did the warrior hop into Deliverance at the very start or only for the last bit? Did he dodge AoEs?

If I remember, the tank had about 38k hp approximate when he was in Defiance stance. I'm in all 270 Shire gear and the 270 Proto-Ultimate Ring of Healing. I'm using the 270 Shire staff. I used Assize, Tetragrammaton, and Lucid Dream on cooldown. At the very start. He would pull with Defiance and once he stopped running, immediately swap to Deliverance and stayed in that stance until all the mobs were dead and then go back to Defiance for the next pull, rinse and repeat. From what I could tell, he dodge some of them at least, not for sure if he dodge all of them.