As Thorauku said, your HP is a bit low. Aim for 4100 HP outside party without food.

The most important thing to learn for WHM in this fight is dealing with Death Sentence and Fireballs. You need to know when a Death Sentence is coming and prepare for it and you need to be able to heal fireballs immediately after hit (I use cure 3 on fireball group). For me phase 2 was the most difficult to learn so don't be scared if it seems difficult at first. Turn 5 is all about practice, practice and practice. You may run out of MP when learning, that's normal too, it will get easier when you learn to handle your timings and cooldowns and when everyone else in the group learns their part too.

There's a previous thread about healing turn 5 with some great advice here: http://forum.square-enix.com/ffxiv/t...=1#post1849910