Antisocial?

Someone described me today as antisocial, which I guess I will admit to. I never used to be I used to love partying with a huge group of people and the chaos and stuff. But since I've made this big life change I've started spending more time on what's hidden under the surface, why I act and do the things I do, and now it's created an anxiety around other people. Insecurities arise about what I'm talking about and look like and talking too much and being fun and honestly it's exhausting!
There is a group of friends I am very close with that I feel like I am being alienated from. I don't know if it's because I'm awkward to be around or I've done something to offend someone. I just want them to realize that interacting with people has become something I've had to relearn how to do. I've lost all my confidence and spark. It's like I'm creating a new person and it's extremely scary. I don't want this new me to be a failure like the old one. It gets extremely frustrating. But I would like to be a social butterfly again. I love my friends and I would really like to get closer to them. I feel a distance between us. I just want to know if it is my fault or just the world changeing. If it is, the world that is, then I'm sorry for letting that happen.
I guess I don't know how to be around other people when I'm probably at my most confidence low.
I just feel such block between us now and I'm not sure how to fix it.