Alone

Why do I feel so lonely. I have my fiance I have this whole community. But this depression makes me feel utterly alone. Nothing is fulfilling anymore. I just feel so alone and empty and annoyed. Why cant I just feel happy or content. I have those that want me to open up to them but I feel like such a nuisance like I'm always dragging everyone down, or if I dont pretend to be happy more those that do care will get tired of trying. I dont want to push people away ot hurt anyone but how can I express this low feeling I have without everyone getting tired of it. My fiance begs for me to open up to her but what if she hates what I've become.