This is going to sound cynical, but it is not in any way. She did you a favor. There was no room in her life for you and she wasn’t going to string you along. I know it sounds shitty but you will get through it.
Perfectly said Tim! When my last girlfriend before my wife and I broke up because she fell out of love, I literally couldn't breathe let alone sleep eat or function. It truly felt like my world ended... it took a while of soul searching and practicing self love and care that I finally realized how that relationship served a purpose to my growth, I refer to it as collateral beauty. I learned from the pain and the overall experience that I didn't need anyone but myself and when I was ok with that, eventually I met someone I truly loved, not needed, and we now have been together 30 years with 3 amazing kids. Its true, you can't see it now but you will, please trust that.
Tom, reread that bolded part back to yourself.

Been through it as well. 10 years, got married, and was told out of the blue that she didn't know if she wanted to be married anymore. And it wasn't even my idea to get married!

Still, it was a world turned upside down event. All I knew and related to was tied into that relationship. The challenge was how to extricate my own experiences in my own life during that time together and make them stand on their own. It really helped the healing process.