I have only called my therapist twice in the past two years. Both times were when I was REALLY having a bad experience and needed her to help me not turn to unhealthy ways to cope. But I am not really one to talk on the phone, I email alot. That is my way of communicating with her.

If I were in your situation, I would ask my therapist what he/she calls urgent. I would rather know up front, than to call and be told, "This could have waited until our next session."