I would send a text or place a call to Rex or her dad and ask if there would be a problem with you attending the church service. You could always slip in and sit in the back of the church...she would never know unless she can turn her neck completely around and see over the heads of others.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.