Why Do I Feel This Way?

It seems like no matter what, I always feel disregarded, ignored, on the outside looking in. I tend to feel overlooked. And I don't understand why. I tend to accept that framing, no matter what I do, no matter how hard I try. I may know something good about myself. But I don't feel it. I feel so on edge, so alone, ignored, and unliked 99% of the time. I always assume no one really likes me as much as I like them. Why? How do I not look at myself this way, not think of myself this way? How do I not feel invisible and alone, even though I am alone?