I unerstand that it must be driving you MENTAL - I'd be the exact same....but I had a conversation with my therapist last night about when you can't stop thinking about things like this - I was telling her how sometimes I just lie awake worry - and she was teaching me this method of distraction where you stop and take 5. So you just take a few deep breaths - in through the nose, out through the mouth and then you try and think of 5 other things....so it might 5 things you need to do tomorrow, or 5 things around you that you can hear at that moment , 5 things you'd like to acheive before the end of the month, 5 people you haven't seen for a while and want to make a point of catching up with....even take the time and write them down