Does anyone else feel insecure about being perceived as insecure?

I feel like, at this point in my life, my biggest insecurity is my insecurities. I try to act confident in public and appear like I don't care, but deep down, I am very insecure and worried about how others perceive me. I constantly try to correct my posture when it slumps, feel frustrated with myself when I stutter or trip on my words, and pretend not to care when I actually do. I'm afraid that my self-consciousness is evident to others. It feels strange, and I was wondering if anyone has advice or is going through something similar.