Hello, I easily get into fight or flight mode which lasts very long, weeks or even months. It's mostly caused by certain thoughts that I have. Let's say that I had an argument (but not something extreme) with person X two months ago and there will be a reason to see him again in a month. So I start thinking how he could say something bad to me next time I see him. My mind starts recreating different situations what exactly could happen or what he could say. And probably because it doesn't get an answer on what's going to happen or if it's going to happen at all, I get stuck in fight or flight mode. 

What I notice though, is that when the situation to see him comes (let's say in a month) and nothing happens, the fight or flight is gone and I'm back to normal. I'm giving this just as an example how I feel and it's not just one person causing it, I feel like this every time similar conditions come into play. I keep telling myself that nothing is going to happen or even if it happens it shouldn't matter/won't seriously affect me, but the fight or flight is still there. Right now I'm stuck in fight or flight again and I really want to get out of it. How can I make my mind accept an outcome, no matter if positive or negative, stop obsessing and simply move on? If I achieve this, I'm almost sure that I'll be back to normal, but I just don't know how. 

Has anyone been in a similar situation and could you please give me some advice? Any help would be greatly appreciated.