Aloha,
It's normal for an anemone to move about, but shrinking to 1/3 size and continuing to move for 2 weeks is not so normal. Anemone happiness has a lot to do with finding a place where they like the water flow and have a good place to hide.
As far as water parameters, what are the Alk and Ca levels
How long has the tank been set up
How long has the anemone been in the tank
If possible, please post a full tank pic (not the stand, just the tank).
Mahalo,
Mark