I think this song is about a person who has a problem with addiction and accidentally has "taken it too far". I think that his "girl" is also a major contributor to his addiction, like in many cases with people dealing with drug and/or alcohol abuse. In many different parts of the song he mentions how he is in a place "so unlike what you've seen" and goes on to describe it in further detail, most people would compare it to "Heaven" or "Paradise"; the ideal Afterlife. Many people that develope an addiction problem wind up dying because of what they are addicted to.
"just giving you a small taste
Of your afterlife here so stay, you'll be back here soon anyway"
I think this exhibits that point rather well, Guy overdoses, guy has near death experience, guy will most likely die as a result of his addiction, even if he suvives it, because many people cannot overcome them once they are buried so deeply in it.
The second part of this song in my opinion is about him trying to move on away from his addiction, not only to drugs, but also to his "girl". The two parts are separate which is evident because of the obvious change in melody with the verses and the chorus. He knows that he has not been living his life properly and in order to find his place he needs to move in the right direction -
"I don't belong here, I gotta move on dear escape from this afterlife
’Cause this time I'm right to move on and on, far away from here
Got nothing against you and surely I'll miss you."
As for addictions go, many families grieve the loss of the person with the problem because that person as they once knew it is no longer the same-
"Loved ones back home all crying ’cause they're already missing me"
And since he knows this, has a second chance at things-
"I pray by the grace of God that there's somebody listening
Give me a chance to be that person I wanna be."
The lyrics can have a few different meanings, but if you put them in terms of someone dealing with addiction there are definitely a lot of paralelles.

It is written in the music, but like all art, it is meant to be interpreted personally and differently by others.