For starters you didn't say what you where taking so it's kinda hard to say how much Arimidex you should use.
If your nipples are hurting that's from already converted estrogen, and Arimidex won't help with that. Nolvadex is needed. Both actually.
1mg Arimidex/ED for a person in crisis. 30mgs/ED on the Nolvadex.