God's Will

Sometimes opportunities arise that I am not able to realize. In an effort to dispel disappointment, I try to decide whether it was my fault that I was unable to take advantage of the opportunity, which helps me sort of decide whether it was God's will.
For instance, I was invited to spend Wedneday night at CS's (a female) house. I ended up not going ultimately because I needed to study more for a test the next day - it was my fault for not studying more ahead of time.
However, that evening my house parents were expecting company that were coming for a funeral. When they arrived I discovered that one of them was a friend (DA) I had not seen for six years (she didn't know that I lived there). If I had spent the night at CS's house, I would not have seen my other friend that night. I might have gone to Campus Ambassadors Thursday evening and may never have gotten a chance to talk much with her. Did God use my procrastination in studying to enable me to visit with my out of state friend? (or was her staying at my house a complete coincidence with no value to it that God cared about?) Is it sort of like God using the ungodliness of the Assyrians to carry out his will?
Or maybe if I had not procrastinated I would have spent the night with CS, found out from my house mother that DA was staying at my house, not have gone to Campus Ambassadors, and have been able to talk to DA Thursday night. In that scenario I might have received the greatest blessing....