A fan whirring in the windowsill.
The walls illuminated by colorful string lights. 
I take a drag of my cigarette and
  flick it over the glass ashtray.
The ember lingers for a moment.

I'm physically alone
but this isn't lonely.
Lonely has been chugging beers at parties to feel like you're part of something.
Then frequent, yet short, disconnections from everything. 
When you hear only the faded noise of the party
and see everyone loving everbody else's company and the only thing you can feel
  is emptiness.

That was lonely.
I'm physically alone, 
but this IS NOT lonely.