I’m confused

I’m confused When I’m by myself I am absolutely fine. When I read something in front of my family I have a MINOR stutter which I’m ok with When talking to friends it’s veryyyy minor When under pressure and maybe presenting (I haven’t presented in years lol I have to present in three weeks tho) it’s complete dog shit ahh I think I can overcome this stutter quick if I have the right mindset, meditate and do breath work My brain is weird. Anyways how can I get over blocks ? And why am I comfortable with my own presence and when reading text sometimes?? Any advice on presenting? I tend to say um a lot which is an annoying filler :/