How is it possible to feel this way?

There are people everywhere, co-workers, family, friends... so how is it possible to feel isolated and lonely?

Perhaps it's not about the number of people one has around them, but the quality of those relationships. Maybe there isn't anyone like me, anywhere, and maybe that's not a bad thing sometimes, but sometimes people just need to know they matter.

Don't take people for granted. If they are important to you, make the effort to let them know that because, one day, they might not be in your life at all. If that's ok with you, you are probably in a good place. If it's not, reach out before those you are ignoring simply stop caring about you.