If you have some health to sustain you a while,
the hammer spell (shaman magic->nature magic->hammer) is your best bet, even at a low level.
Unlearn another skill if necessary and invest in it. This spell does bone damage, to which the shadow creatures are extremely vulnerable.
Just run around, make them follow you and cast the hammer spell. Usually if you cast it once or at most twice al those shadow critters following you are dead.
