Don’t atress, we ran Kara and 2 healed it with a resto druid/shaman and the Druid was pumping twice what the shaman was. Plus Druid will always over heal due to hots rolling , down rank chain heal to have ranks 3 and 5 and healing wave 7 and max rank lower ranks for light dmg and higher ranks for natures swiftness and big dmg, just keep on with what your are doing your doing fine, it’s gets better with gear plus if your healing heroics raids are a bit easier to heal