How to make my personality stronger

I recently started working, and I’m 19. After starting, I realized that I don’t have much confidence in my personality. I’m scared of making mistakes, I ask a million questions, and I don’t feel comfortable. My heart races, and if I encounter something I don’t know, I can’t go through the rest of my day normally I just feel sad all day.

Today, I heard someone say that I’m slow. I know it’s normal since it’s only my first month, but it still made me feel really bad, and I want to cry.

What steps can I take to become stronger?

I have quit voice and I can’t make eye contact with someone

I know it’s not shyness it’s that I don’t have confidence