How do I stop playing the situation over and over in my head again wishing for a different result?

Well one way, you can imagine the situation and instead of it happening like it always does, imagining it ending in a way you would have liked it to. Memories aren't static, they aren't even a depiction of what actually happened. You can really bring a lot of growth and healing be rechoosing how you would have liked the event to take place. This helps rewire your brain in a more positive way for the future and can relieve a lot of hopelessness.

I recently had a job that I ended up leaving after almost 2 months because it was a very toxic work environment and I went home crying every day. The reason I say this is because I had given up a different job in an area that I was very interested in, for this job that turned out to be horrible. When I left the job, over and over in my head I thought - "I can't believe I gave up the other job. I can't believe I decided on this instead". The thing is, I made the absolute best decision that I could with the information that I had at the time (which I won't go into detail about here). There is no way that I could have known what the work environment would turn out to be. There is no way that I could have known I would hate the job. Using the facts and information that I had when making the decision, I made the decision that I thought was best. Even though people say it all the time, hindsight really is 20/20. You can always see what you could have done different or better after the fact. All you can do is just be sure that you are making the right decision for yourself, at the time, with the information that you have. When the situation is over, or after something happens, yes, you may look back on it and think "I wish I had done that differently because now I know _________"; but just remember that you made the right decision at the time. Don't focus on stopping the rerun of the situation...instead focus on the fact that you did everything in your power to make the situation work. And if you didn't, then you know that next time you are in a similar situation, or in a situation that has a lot at risk or requires a big decision, you know that you need to stop, think, and evaluate before acting.

It's an easy trap to fall into. I've found it helpful to see if there is anything you can learn from the situation. When you figure out what you have learned, or that there isn't anything to learn from it, its easier to move on and focus on your present and be more aware in the future instead.

Accept that it is in the past and from here on out, the only thing you can do is try to make the future better.

You can stop playing the same situation over and over in your head and wishing for a different result by occupying your mind with something else. Talking to a close friend helps more than you think :)

That can be difficult. There is no one answer fits all. Everybody is different. Perhaps try concentrating and focusing your mind on what you can do now, in the present time. Make lists of the good and positive things going on now.

Play music loudly/quietly, pictures idealistic scenarios. The gravity of the situation is part of someone's reality, it doesn't have to be a part of yours

This sounds like a difficult situation, sometimes just picking up a hobby or finding distractions can be helpful. When I had gone through a tough breakup that was really tearing me down, I took a moment to stop thinking and re-evaluating. I then picked up playing the ukelele and working out to start gaining control over myself again. Little things can go a long way. My advice, try something new, try something you've done before but dropped! I wish you luck fellow human! I hope you are well and know that this stranger is rooting for you!