Well, Psy...
I'm sad to hear how hard this is for you, and I'm sure others here feel the same. You are not alone!
I just went thru something very similar, and felt much as you have described. I came here with my story and sorrow and questions and got helped!
I've also done lots and lots of reading....books to help one thru this. One book talks about trying to view this experience as a "new beginning" rather than an ending. These feelings you have are telling you that you are very much alive...your feelings are raw but your senses are also very keen at this time. Try practicing "being in the moment", concentrating on your surroundings, how things feel touching against you, your breathing, what you're doing at that specific time. Each time a thought of her comes to mind (and I realize at the early stage you are in, it's most all the time!), train and force your mind to refocus on something else, even your breathing. It feels like small baby steps at first, but eventually it will help you, and even when you have only a few minutes of clear thought, it's a big victory.
I want you to think about another thing too, Psy....Do you really want to devote so much of your emotional energy on someone who has rejected you? Think about it! You are worth so much more and your precious thoughts and ernergy can focus now on your own recovery.
Sending calm and peaceful thoughts.
Seeker