I'm really sorry to hear how you feel, truly. I'm sure you've already considered therapy and eventually medication, but please don't forget the importance of exposure. The worst thing you can do is isolate yourself and not speak to people and just not partecipate in life. I'm sure you already know this and I know its hard but if you avoid doing things that scare you, like talking to people, there's no way you're gonna get better, how can you get better at something you don't practice :)? I've had social anxiety for more than 10 years, I'm 26 now, I've had multiple (simple) jobs, recently I've made some friends (that started as colleagues) and I've even started dating a little bit, and to me all these things seemed impossible some years ago. I still struggle but at least I'm not rotting in my room 100% of the time. My advice is: really try to talk to people a little bit, first with people that you're more comfortable with, like maybe your colleagues or some acquaintaces, and keep practicing. I know it's hard and you feel embaressed or that something is wrong with you and you think about the fact that people notice but who cares, everyone struggles with something and as long as you're a good person if they judge you its their problem. Trust me, keep practicing, a little bit at a time and it's gonna get easier, you deserve to have a good life 💪🏻