I feel like it's linked to my body and mind.

I feel ashamed on a social level. I never talk to anyone, really. Unless it's work or someone I've known a few years.

I can't find it in me to approach anyone because a few times I did it they just straight up ignored me. Or I found I had nothing to say.

There seems to be a mental block or a lack of thoughts in my head. I can make surface level "How are you" conversation but going beyond that feels impossible.

I also feel that I genuinely lack interest in others.

I hear people talk all around me and I feel like they just got something I don't. I don't understand it.

It goes like this sometimes, sometimes I'm much better and can be social but those moments are far and few between.

There's also a thing where I can approach people if my friends are around and spectating. It's a weird phenomenon. Suddenly confidence around people I know.

Any advice, please?