What should I do?

I’m a younger guy and am in my first relationship we have been dating for 5 months now I couldn’t believe at the start of the relationship I was pulling someone like her but now it feels like she’s really clingy and I don’t have the same feelings for her anymore. She texts me everyday about stuff and sometimes I don’t wanna talk because at home i just wanna play on my computer but I think it would be rude not to. She also stalks me every time she sees me she looks at me and I don’t even know she also knows everything about me cause she’s memorized it. Now I’m losing my interest in her and feeling like she’s not herself anymore she used to have a great personality and that’s why I liked her but now I don’t even want to hold hands anymore because she’s just clingy. She’s also an introvert which i have no problem with but I’m a big extrovert and talk to a lot of people at school and she gets sad when I talk to them instead of her because I wanna talk to my friends we talk and text everyday and it’s getting exhausting sometimes It seems like she’s relying on me and I’m the only person she can talk to even when I wanna talk to other people she also went on a rant once about how ghosts exist and why they do and I personally don’t believe that and she kept going on about it she also believes way to much about zodiacs. She also has body dysphoria and keeps going on about how she thinks she’s ugly and it gets annoying I’m just kinda losing my interest but I know how bad she would feel if I broke up with her sometimes I feel like she’s a good friend and good to talk to but I’m not sure if I want it that serious with her also she threatens that if I broke up with her she would tell all my secrets

So my question to you is what should I do?

As much I used to like her she doesn’t feel the same anymore but I know if I break up with her she will feel guilty and sad

TLDR; my gf doesn’t feel the same anymore and I wanna break up but I know she will feel horrible