ADHD/Autism?

I made a post on here recently about how I am with feelings, friendships and socializing and a handful of people suggested maybe I have ADHD/Autism. Everyday I overthink the things I do because I believe I do have it and here’s an example but i don’t know if this is just social anxiety or adhd. My gf told me about plans we have on Wednesday and I assumed it was just going to be us and a couple other friends so I mentally prepared for that but my gf just told me there is going to be 2 more people coming that I don’t really know so now I don’t want to go. Conversation is really hard for me when Im sober that’s why I usually drink but I’m trying not to drink anymore because I have addictive tendencies. And the thought of having to sit there awkwardly when I don’t know how to start or continue a conversation or that well and I really don’t want to put myself through that but my gf insists I go still. Its a friends birthday but even socializing with the 2 other friends I initially thought would be the only ones we’d be with, is hard as hell for me and I hate it. My mood is completely different now too like my mental plans were ruined.