Well its realy hard too see what your doing but from my POV im wondering why your not using: (well its hard to tell if you do use them or not)

Psy scream (aoe fear)
Blast Wave (since your specced fire/arcane?? well the damage is awsome, it knockbacks and slows)
Frost Nova
Mana shields
Invsibility will break follow i guess but damn it must have some cool settings to use them in! go figure it OUT!!!

You seem to panic when people come close and i alawys did that on my lock it just takes time to learn to relax etc..

Drop the buffing/running to blacksmith as no one needs to see that even to comment it!

Can you play a mage or priest well as one toon?

My suggestion is to read pvp guides for both mage and priest, and to learn the key tools..

Have you considered dropping the priest when your pvping? I play like shit when i go with my paladin+4 shamans.. When its just my shamans do fairly well!

Both mage and priest isnt a straightforward class to play solo either and boxing them cross class certainly isnt easy at all!

My tip is to take a day or two and play solo to get a feel!