Hey, first of all, please dont worry. Starting uni is hard, and finding it difficult to settle in is normal. I am just starting my second year, and I remember a year ago I was in a similar situation; I have social anxiety as well and found it incredibly difficult to talk to people and felt like I had made a huge mistake going to uni. All I can say is it definitely gets easier. It may take a while, but it WILL happen. I wouldn't say I've made "friends for life" at uni, but I have definitely made friends who I can meet up with, and really, that's all you need right now, and you will find those people, if that's something that you want. Also, really don't worry if you don't meet people from your course - no one talks in lectures anyway.
A very good way to meet people is through societies, you get to meet people in a chill environment and you already have a shared interest, so there's already talking points to get started with.
I think something I wish I'd known a year ago is that it's okay not to do every single thing that's on offer, and it's okay if you don't have the same uni experience as everyone else. It's okay if you don't want to go out clubbing every night, or if you find it hard to talk to people. What helped me was accepting the nerves and the fact that I am an introvert - as once you accept that part of yourself, you can stop punishing yourself for not being able to do the things that you feel like you should be able to. Because ultimately, you must only do what you feel comfortable doing, and it will all work out in the end. I hope that it starts getting easier for you soon, if you have any questions or anything feel free to ask me, I'll try my best to help.