You fell in love with a hooker, and almost married her.  You got lucky, in that the likihood of this being far more traumatic were very likely if this lasted. Now, you mentioned this was your first love; that is telling, and you are going to need to figure out why her, and how you can move on without being so vulnerable to someone who was perhaps not the best person to fall for. I am not going to suggest why- I do not know you and could not say..
I say this in all seriousness, with no malice or judgment; what you need now is psychotherapy to help you unpack how and why this happened to you. While you may get some "interesting" analysis here, I suggest that some things are left to a professional. There may be some "generalizations" that can apply to many in your situation, you are going to have some work to do. After reading your story, I would suggest a male therapist. 
Good luck..
PS...if you CAN Phuck your brains out somewhere without THINKING about falling in love, that would be good therapy also 
