Medica uses a lot of MP, maybe switch to fast healing with Cure I instead? I usually fast heal the group with Cure I instead of Medica (I only use Medica in emergencies cause of the MP cost), but your spell speed should be high enough that you can dish out Cure extremely quickly.

Pay closer attention to the MP cost and try to use the less MP hungry abilities maybe? You should have a high enough Mind stat that the lower Cure shouldn't be bad.