How can I get my Facebook messages hidden from everyone?

[Izzy]

This person I used to be friends with keeps taking screenshots of my messages and posting them on his statuses and I want to get my Facebook messages hidden and say "Marked as spammed" so nobody would keep taking screenshots of my messages and I just started dating a girl I used to hate and I used to talk shit about her to my old best friend and I feel bad about the stuff I said about the girl and now my friend kept taking screenshots of my messages and posting them everywhere and I am worried that my girlfriend would think I still hated her when I said those messages months ago and I accidentally said my girlfriends secret Facebook account that she's been trying to keep hidden from people trying too troll her and I accidentally told some people what it was and I am worried that she'll never forgive me for what I did and I am paranoid that my old friend is going to keep posting my messages online and I've tried everything too get my self reported. I kept posting porn on my Facebook account so I would get reported and my account would get banned but its not working. I just only get blocked for 3 hours when I am trying to get my account banned and
Nothing is working so I really need help trying to get my Facebook messages hidden from everyone I used to talk too because I am just scared that they'll keep posting screenshots of my messages and I even tried to report the trolls that kept doing that too me but Facebook won't do shit about it D:

[abraXus]

there is no way to hide your private messages from the person you sent the message to

and there is no way to prevent someone from taking screenshots, all you can do is report the person's status update to facebook as something that is violating your privacy