If you don’t have anyone, then look for hobby groups. There’s groups out there for almost any hobby, so you can get to know people through that. Doesn’t even have to be in person, if the thought of meeting new people irl triggers your anxiety. And if you’re bad at talking to people then you need to practice, fail and learn from your mistakes.
If you have the desire to improve, you’ll manage. Just take it slow and don’t force yourself to get into very uncomfortable or new situations right away. Like, for example, big parties.
Over time, you’ll get better at improvising during conversations and you’ll get more confident. And if there’s people who try to shit on you for trying your best, don’t worry. They’re actually a lot more insecure then you’ll ever be at that point.