People do read your posts. To check how many people read your topic you can check the number of views (on the right of your thread's title).

As for the replies, that's a question that is periodically asked here. PC is a huge community, so not everyone can read every single new topic: there's too many. Some of the "regular" members (myself included) usually try to write a reply in those topics that go unanswered even if we don't have much to say. And this is so no one feels ignored or not important enough.

There really is no reason for you to feel unworthy. I firmly believe that every human being has an innate worth, regardless of how bad life's treating them, and so do you.
Also, people often click the "thanks" button if they read but didn't have time to reply or wouldn't know how to support you. It's good to check the bottom of your posts for that, so you know people care even though they couldn't reply.

Take care.