Are you talking about anxiously ruminating on possibilities of a situation that may never occur? That sounds like it might be a sin of not trusting in God, or it might be a mental health issue. Some people really can’t help being unduly worried.
How I deal with those nagging worries that try to destroy my peace of mind: I look back to situations in my life, where it was obvious that the Hand of God was at work, and remind myself that He has never let me down, even in situations of my own making, and has always given me either the spiritual resources, the temporal resources, and quite frequently both, to deal with the situation as it works its way out. And in a few of those times when prayers have seemed to been unanswered, I later found out that what I had so desperately wanted at the time turned out so awful that I would have probably gnawed off my foot to escape!