Alone.

a·lone  

/əˈlōn/

Adjective Having no one else present; on one's own. Without others' help or participation; single-handed.

Synonyms lone - single - lonely - lonesome - sole - solitary

I understand the meaning of the word, this is not my issue

A statement, a feeling, either way

I still miss you

The notion that one can feel alone in a crowded room

is not foreign to me, I am who I am

Alone.