dont let yourself discouraged. MP-Management as a WHM is the one big limiting hurdle you have to master. Even later on. The WHM can be a insane healing- (and even AoE-Damage-)bomb. bit it's drains you out in no time.

therefore, as many people saidd before me. try and plan the fights. if you dont know them, keep your healing low - if you have any chance - remain on Cure I and wait for procs. if you have to spam Cure II - the fight have to be over quickly.

As i just reached lvl50, my gear was weak ofc, but many tanks thought they can pull like your are fully 100+ geared - is used to spam at the begining of every dungeon "Dear tank, my gera is still crap, please dont pull to much"

some listend to this request, others prefered to go into the bright light of death - their choice.

you should always try to analyze the capability of the tank you have and communicate how much he can take and force him to slow down. (it's even easier if it's your personal tank^^) DPS sghould always do what is possible to mitigate avoidable damage as much as possible - if the dont (remind them of the bright light of death from time to time)