Feeling embarrassed about having social anxiety

I'm sitting here in class, alone, staring at the computer for hours, watching others talking to friends etc., and I ask myself: "is it possible that at 20 years old, one must still be afraid of people who don't think about you at all and if you walk in a strange way (for example). People who are also quite nice! I have moments in which I'm ashamed of how I am so "childish" let's say, as if I see others as enemies... too bad that this doesn't help much to push me to get out of it.

Anyone else?