Regret/ Never regret

I always tell myself not to regret for things I done, but I just can't follow it.

Just always feel sorry and sometimes even angry for those desicions I made or actions I done, all these make me feel uncomfotable and guilty, sometimes can't breathing at all.

I did told myself not to think anymore, stop it, but I just can't stop blaming myself. When it comes up, it lasts for days.

Just like a nightmare following my steps, makes me crazy. I have no way out.

Is it all b'coz I am a Pisces?