So awkward around my parents

When I go out with my mates or by myself I am pretty darn confident. I can easily make small talk with shopkeepers etc.

But when I go out with my parents to buy and try on shoes I just get so red faced and embarassed and awkward.

It sucks because my parents must think im a weirdo.

There's literally no one else in the world that's known you for as long as your parents/ They brought you into this world, they changed your diapers for years, bathed you and put you to bed at night. Even if you dont have a great relationship with your parents I dont see why you should have any reason to feel awkward and uncomfortable around the two people that you should feel the most comfortable with. This might imply some deeper issues in the relationship with your parents or just simply reflects something about you and whatever strange reason you have for feeling awkward.

In my entire life, despite my bad history with my parents, I have never experienced awkwardness with any of my immediate family. It should be impossible to have awkward silence or feel awkward with people you've spent your entire life being around, did you not spend much time around them growing up? You clearly feel more comfortable and familiar being around your friends than you do with your parents - nothing wrong with that but I do find it unfortunate.