I'm at a loss for words

I have a very specific issue here... I’m honestly not sure if this is actually social anxiety. I want to stay quiet about it, but is there anyone else out there dealing with this who *doesn't* have social phobia? Because at this point, I am questioning everything.

I genuinely love being around people. I love people! I feel absolutely miserable when I’m alone for too long. But I have this one peculiar problem when I'm in a crowd. When we are in a group and I'm talking to more than two people—specifically when they are spread out in a way where I can't catch everyone's eyes all at once—I completely lose my focus. It isn't that I'm afraid of my flaws; I don't care if people stare at me. It's just that when I'm speaking and multiple people are listening... I simply cannot tell a coherent story. My mind starts racing through a dozen different things in a single second, yet I can't grasp even one of them. A total black hole opens up in my brain. I have to strain myself just to remember what I was supposed to say next. Everything turns into this chaotic confusion, so I end up cutting my story short and just blurt it all out in one breathless, monotone rush.
Okay... social phobia? It feels awkward to even discuss, and maybe it's only a little bit... but it has escalated to the point where I can't finish a story properly. I mean, I *can*, but it's poor quality, and it seems to be getting worse over time.
Another thing: sometimes this happens totally unexpectedly. I'll surprise myself. If the group dynamic changes slightly, the problem vanishes, and it feels like my brain has suddenly "cleared up."
It's the same in one-on-one situations. Sometimes I feel extremely uncomfortable, and other times I'm genuinely surprised by how smoothly I managed to navigate the conversation. Then, the next time, I might suddenly go silent with the exact same person I had a great experience with just before.
In the end, I have no idea what this actually is.
I fall into the Highly Sensitive Person category, but if I really am that sensitive on such an unconscious level, it feels like a bit much.
I also struggle with chronic sinusitis and occasional headaches, so I truly hope this isn't something physical.
The worst part of all of this is that because of this issue, I can't seem to build new friendships anymore. Once we reach that stage where we realize, "Hey, we get along, let's keep hanging out," I show this "other side" of myself. It always ends with me retreating into my own confusion, leaving people with the impression that I'm someone they can't rely on.
It's sad, because that might actually be the truth. But I love people, and I want to stay close to them... with some, I want to be even more than just friends.
.....
Please, people, help me. Does anyone have similar experiences?

What other physical symptoms are you dealing with right now?

Is this bothering you because of what’s actually happening, or just because of what you think everyone else expects from you..?
I feel like anxiety usually leaks out through body language, and honestly, that nervous energy can just eat you alive... maybe you're feeling like you aren't coming across as "alpha" enough or super confident in what you're saying? It makes it hard for people to really latch onto what you're saying—especially in a big group where some people are just naturally chill, or they've got that knack for storytelling and keeping everyone hooked...
The thing is, it feels like you're turning something small into a massive deal in your own head. Just try to relax and be yourself—like, the real you—instead of trying to force some version of yourself that just isn't clicking... Not being the life of the party doesn't mean people are judging you negatively. Let others do their thing, and don't hold yourself back just because you've convinced yourself you aren't interesting enough or that people are looking down on you... You'll know if someone actually doesn't like you when they actively distance themselves, but right now, you're creating that gap yourself based on stuff that isn't even real...
Just breathe and enjoy yourself... If huge crowds aren't really your vibe, don't force it. Only speak up when you actually feel like talking...