I do this. Also, I tend to start to try to "fix" it in my mind, but of course I can't fix something that has already happened, so I get bummed out that it's left unresolved.

You mentioned in your initial post that you also tend to talk out your problems and sometimes speak out loud. I do this as well. I don't think this is abnormal at all, I think we probably just think more about things than others typically do. I have noticed that since I've been taking anti-depressants and anti-anxiety medication, the pessimistic conversations are less frequent. Not saying that's the 'cure' but it's helped me a little to not feel as overwhelmed with my thoughts.