I have no friends at school, and I'm struggling badly with social anxiety. What should I do?

I’m already in Grade 10, but until now, I still don’t have any friends. I can’t report in class, and whenever there are group activities, I’m usually left out because I can’t talk to them since I’m afraid of people. The only good thing about me is that I’m smart, but it feels useless if I’m like this. I feel like I won’t be able to graduate anymore. I feel like I’m slowly just accepting that there’s no hope left for my life. Even my classmates avoid me, and some of my teachers get angry at me because of the way I am. I keep trying to change, but it feels like I’m slowly losing hope. I know my family will be disappointed in me because my uncle is successful—he graduated and got a good job. Being smart feels useless if I’m still like this. I don’t know how to talk to people, and everyone thinks there’s something wrong with me. I also constantly experience bullying because I’m extremely quiet, or sometimes just because I’m always alone and have no friends. Some students even laugh at me while I’m walking home.