Sounds like you are ruminating over the events in your past. This often happens if our needs have not been met or because of some unfulfilled desire. But it almost sounds like you are being hard on your self too and there are lots of things in your mind asking for an outlet.
Next Steps
Counselling sessions will help you get that outlet, also figure out why this is happening and what can you do next.
Health Tips
Write down your thoughts and feelings. Give it an expression. Start maintaining a journal.