I'm so sorry you are feeling nobody cares.
I mostly just greet new members here on PC. So I don't know you. And I don't know why other members would not care about you.
But I do think you are correct in terms of people in real life. My experience, over the years, has been that nobody wants to hear about anyone else's mental health concerns. People will stick with you for a longer time, or a shorter time, depending on how important a person you are to them in their lives. But there's a limit. They don't know what to say or what to do. And, besides, they have their own problems.
In my life, as long as I was willing to play along, & try to be the person other people wanted me to be, they were more than willing to let me. And they didn't really care what it might be doing to me inside. I suspect a lot of us, here on PC, have had similar experiences. That's at least part of why we're all here.
Anyway... (me thinks I digress)
I don't know what has caused you to feel no one cares about you or your posts here on PC. It is true, I think, that sometimes members posts get lost in the shuffle so to speak, not intentionally, but just because PC is such a big forum & things tend to move so quickly. Hopefully you will receive lots of caring replies to
this post.