Just social anxiety or something more?

I was diagnosed with social anxiety when I was 9, and have been on Zoloft since I was 12. I'm 15 now and my biggest fear is being in any sort of emotional connection. it very well just be something all teen go through. I get it, I'm young, I'm still learning,, but It genuinely terrifies me. Sure I have friends. But anytime a person expresses wanting to have an emotional connection I automatically cut them off and shut down out of fear. I know it's wrong, I know I should try. But the thought of being vulnerable in any sense is not something l'm comfortable with. I feel like an awful person. I'm actively hurting people by ignoring them. I feel so guilty. A real time example of this is a friend I made a year or so ago. I genuinely enjoyed his company. But after a while he grew attached, became clingy. Suddenly wanted to talk emotions with me. And that's a good thing, I know. But for some reason my response was to emotionally distance myself. Now I have over 30 messages from him asking if he did something wrong. He fucking blamed himself. I didn't know what to say, so Regrettably, I left him on read.. I mean what is there so say? That l'm a shitty person who can't handle affection? That his need for constant reassurance to feel good about himself is too much for me? I don't know anymore. I just don't want to hurt him anymore than I already have. I don't know what's wrong with me. My therapist says it's just my social anxiety flaring up. But l've always felt like this, and I need answers. So l've turned to Reddit, i feel like there has to be other people with similar experiences. I just need to know I'm not crazy.