Hey Aaron,

I ain't going to discourage you doing what you feel you have to do as a friend, or as needing to take hold of life etc... but I have a concern with this:

"because if I lose her, that is it for me. Not that I will kill myself, but apathy and depression will consume me. It nearly took me this past couple of years. I know this would be the capstone. I can feel it."

Bro, what ever you do, can I please encourage you to establish your view of life on some other foundation than this relationship.
She is obviously highly dysfunctional and so are you. This relationship is going to be fraught with problems and trouble and struggle. You need to be well grounded somewhere else in order to survive and function well in it.

Of course I encourage you to have Jesus as your foundation.
Practically this means, cast your worries on Him, seek first of all to work on your fellowship with Him and to serve Him. To Prayer and the Scripture boy! Set your hope on being with Him now and into eternity and your hope for this girl as second to that.

Secondly, get into some real life face to face fellowship. Get connected to some other real people so that you have a variety of people in your support base. Even if you go to England, make hooking into a fellowship one of your first priorities. I think you would be foolish to face life alone especially with what you are walking into.

Otherwise, Godbless you as you go. Give it your all. Keep it holy before God and may His peace rule over your anxiety.

Love you brother.
Blessings
Cat.