holy priest or a resto shaman
They're both 100% perfectly fine all the way through level 90, 5m heroics, and LFR, and both completely capable of doing normal raids.
Also, your holy priest doesn't just go OOM all by himself. What are you casting in the situations where you're going OOM? Have you tried a different approach?
The thing with Holy is that it is incredibly good at converting mana into healing. Lots of mana into lots of healing. Very fast. This is actually a huge advantage when you need that much healing, but at your level, you don't. You need to learn how to throttle back.
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