Is it normal to feel insecure around my best friend?

Incoming ramble :)

We havent talked in a little over a week, we usually call daily but we had a little argument. When we finally called again i was met with someone who i could tell was her but she had an insane glow up. Ive always found her to be the most beautiful girl in the world and ive never understood why she always thinks she looks ugly since so many girls and guys want to date her. Today we were playing a game on roblox and it involves singing, her voice is genuinely beautiful and while we were playing i just start feeling like i look and sound awful. She keeps saying how horrible she sounds and looks, it just has me wanting to cry. Ive never felt this insecure until right now. Is this something other people feel or does this make me a bad person?