So far you list fear of losing hear or being without her. What else is there?
Do any points in this article resonate with you?
How about feelings words -- do you have enough vocab for feeling word expression? http://www.cnvc.org/Training/feelings-inventory
How about a list for describing needs? http://www.cnvc.org/Training/needs-inventory
How about "When ____ happens, I feel ____ in my body, ___ in my mind, ____ in my heart, and ____ in my soul because my need for ______ is not met."
Don't worry about it making sense or not. Just list whatever it is and leave blanks if you cannot fill it out yet. Maybe that could give pointers to where THE THING lives. Or what THE THING could be from clues.
Just some links to try to help you start the process of "Naming the Un-nameable."
That's the first step in trying to sort yourself out. ID the stuff, name the stuff, get a handle on it.
It's hard to find advice for how to deal with THE THING if you don't know what you are looking for or what it could be called.
Hang in there.