Hi there! I’m new to this forum, but after stumbling upon your post, I felt an incredible connection to what you wrote. My name is Marina too.
(Though honestly, maybe no one should be named Marina!) Don't tell me you're some kind of water nymph, or we might all be in trouble—just kidding.
I went through those exact same feelings, but I promise you, it passes. I’m 21 now and feeling wonderful. You seem quite sensitive, which usually means you have a creative soul; creatives tend to be highly sensitive and full of contradictions—one minute I'm perfectly calm, the next I'm hyperactive, among other things. Just learn to embrace who you are, and everything will fall into place. I used to struggle terribly with perfectionism, but for me, prayer was the only thing that truly worked. Even when I dealt with terrible insomnia, social anxiety, and nervous tics—which was honestly a nightmare—I never turned to medication. Everything eventually cleared up, thank God. I never resorted to self-harm, and I truly believe that nothing short of God can offer real salvation; I am living proof of that. Just stay persistent and surrender those dark thoughts and heavy emotions to God. If you can manage even five minutes of prayer a day, do it—really mean it. If you put Him first, He will gradually help you transform those difficult habits. I also highly recommend the Brigid prayers; they are incredibly powerful, and you might start seeing a shift after about a month. Good luck!