I suck at eye contact too, I asked my parents some questions about my childhood and it seems I already showed signs of autism, which isn't too shocking for me as I remember isolating myself from other kids and staying with adults instead... I never had many friends and as I've told my therapist I learned body language through books.
I already stim and it calms me down, I always thought it was nothing much since my stimming is just moving my leg up and down, I always thought it was because of my anxiety.
Well, thank you for the ressources you're really nice.
I am not in the USA