You were doing fine, sounds like the party was dumb. It's a WHM's job to heal but the rest of the party has to do their part to minimize the damage they take. Since you were fighting raptors, I'm guessing they all crowded around the back of them and got murdered by their Scythe Tail (I think thats the name of it). Also, at the end of the day, sometimes the stars will align and shit will hit the fan for whatever reason.