My Thoughts

How do you know what thoughts to push out and what thoughts to keep. To me they're all worth keeping but I'm always overwhelmed with them. Is there a way to actually not think about something? just forgetting it? Or is that just some fantasy that someone made up? Yet do I actually not want to think about all the mistakes I have made throughout my life? I have made many mistake throughout my 19 years of life and I know that mistakes are the way we learn but still having to relive it every 5 effing minutes? That's just bullshit! I get it. Don't do it again. So why can't it go to the back of my mind where I don't think about it but its still there? I live till I die and I don't want to relive this for the rest of my life! I want to move on learn and live not fricking learn and relive the past! Is it depression that causes this or it it my own subconscious that refuses to let go? Did I actually learn something or not? Am I supposed to do something about it? If one of my mistakes hurt someone am I a bad person? Will I make more mistakes because I try to live life to the fullest? How do I make a mistake right or am I just going to have to live with it? And how the hell am I suppose to know if it even is a mistake for could it not be a blessing in disguise?