Any advice on how to stop overthinking or dwelling on the past?

Hi Reddit,

I have been struggling with stress and anxiety related to overthinking. Usually it is related to reliving past experiences where I felt like I let myself down (ex. unrealized expectations or unmet goals) or was let down by others (ex. friend break up over trying to do the right thing and being punished for it).

I don't regret the choices I made in these situations, but for some reason it's like I can't get closure on them. I don't know if this would be considered intrusive thoughts? Probably not? But either way, it sucks having racing thoughts and negative memories playing frequently in my mind, especially when I am trying to go to bed.

Does anyone have some helpful tips or tricks for dealing with this that worked for them personally? I know some of the basic advice like get up and distract yourself etc. But that's very hit or miss for me.

Thanks :)