Feeling lonely when not alone

Its one of the worst feelings to be in a relationship and feel so alone. The thoughts of what can I do to make the feeling stop are always crashing around in my brain. The feeling always is immensely worse when its time to sleep.

Living days filled with anxiety then coming home to a household just to feel alone is maddening sometimes. Sometimes I think Im doing it to myself, having a tendency to live in my head. Others, I cant help but feel wont get better even if I didnt do that.