I may be big and ugly, but believe me. Nobody is laughing at you! I was like that before too, but now I just don't care. If somebody is giggling in the crowd with their friends it's probably because they told a funny joke or showed a meme to them. Yeah, it's easier to say than done because even I haven't fully stopped getting nervous when somebody is laughing in public. But time will pass and you will stop thinking about those little things and start enjoying your life!
My height is 178 btw. Not really tall. Everybody tells the same. Until they learn that I am 14 yo ;-;. 178cm in 14 years is bigger than normal height for 15cm. So yeah, have a nice day cool stranger, and believe in yourself more or some sort of other cliche shit idk.