This one was tough for my 5x shamans as well. Here are the keys to the fight as I see it:

- Keep your backs to the wall like you did
- Keep Water Shield up as much as possible (its a long fight)
- Make sure you have a key for Mana Pots (its a long fight)
- Make sure you have a separate key for Stoneclaw Totems, and keep those babies up as much as possible.
- If you have stoneclaws that are out and active, try not to use AOE because the AOE damage will make it so they don't aggro the mobs.
- If you dont have stoneclaws active (cooldown), Chain Lightning and Fire Nova totem like theres no tomorrow.

Took me 6-7 tries to figure this stuf out.

Also, check out the 5x Shamans PVE wiki page... I listed a healing/dps macro scheme that I use that works pretty well (if someone needs healing, you hit a button and 2 shammies heal him while the other 3 DPS the target)