Am I the only one?

I feel like I’m the only one who can’t cum from oral sex. I feel so bad because my boyfriend tries so hard and it feels good but not good enough to cum. I can’t tell if I’m just in my head about it. I also cant cum at all from penetration or being on top. So basically the only way I can is using a vibrator. If there’s anyone else out there that can’t either any advice would be appreciated! 😊