Insecure and really really dead on the inside

I lost all my friends over year ago because I was feeling insecure. At first it was because other kids were making fun of me like a friend would casually roast someone, but they never spoke to me so it hurt in a way that I didn’t know how to handle, eventually it escalated to the point my grades dropped and I dreaded school, but my friends just laughed along. I kept feeling insecure, then one who caused a bunch of drama multiple times one sent me this:

I stopped asking for advice or comfort and stopped myself before I mentioned anything that had to do with myself or my feelings, which was difficult because that’s when I needed them most. The one who called me “whining” was the only one I felt safe sharing my emotions with, the one that “just doesn’t care,” I had a crush on, and “her best friend” was my best friend since preschool. We even had a ten-letter version of BFF. I still have it stuck in my head that opening up will literally kill me and/or my friendships. I have new friends now, and a boyfriend, who I’m especially scared to open to. I know I’m being unreasonable, and that I shouldn’t want to hide, but the voices just won’t go away. I hear everyone I care about screaming at me like I’m a murderer in my head at random points in the day, mostly when I’m happy. I don’t know what to do at this point. I just want to stop it. I want to be happy without consequence. I don’t know what to do, and getting help or even a diagnosis is impossible at this point. If you have any advice, I’d love to hear it.