OMG, I use to do this all the time. It was terrible. I would always have to work out all the different possible outcomes so I would be prepared. I'd have all these conversations going on in my head of posible outcomes. It got to the point I wouldn't answer the phone because I wouldn't be prepared.
Then I relized that I had to stop guessing the outcome. No matter what I did I couldn't control other people, places or things. So I fired the committee of idiots that were in my brain but sometimes they sneak back in.
I would agonize over making decisions based on all my possible outcomes to the point that I wouldn't make a decision at all. When I started making decisions based on what I wanted and what felt right for me then I stopped worrying about the outcome
I compare it to living in the solution instead of the problem. That one use to confuse me too. But when I stopped focusing on the problem and end the pity party, I could start looking at possible solutions again just doing what feels right, not relying on a specific outcome. There is no way we could predict all the possible outcomes of any given situation. There are just way too many variables.
We make decisions every day that are going to affect us one way or another. As long as we are comfortable in our head, heart and gut them you higher power will look after the outcome. Remember, his will, not ours. They say our higher power knows better what we need even if it isn't what we wanted or expected so leave the outcome up to him. It's all easier said then done but it works.