How to move forward after 4 years together...

Hey everyone, I'm having a very hard time coping through a break up and I feel like I need to talk to someone about my internal struggle and heartache. My family is homophobic so they're out of the question. My close friends were my ex's friends so they can't give me any advice, so I'm left struggling on my own trying to move forward and not spiral into a depression.

The background of my situation is like this:

My ex girlfriend and I were together for 4 years. At first we met online, but after a year of doing the whole long distance thing, she asked me to move in with her. I'm from New York and she lives in San Francisco, so that was quite the move. But I did it anyways because my parents are homophobic and being at home living with them was a ticking bomb.
After I moved in with my ex, things were good for the most part, but then we kept fighting and arguing. Somewhere along the lines, we fixed it by having better communication and etc and we were doing great again. I paused my life for her. I took a break from college to be with her for 2 years. A year ago, I decided that I wanted to go back to school and come back to New York to finish school here since it was cheaper for myself and also we were back on arguing and I felt like I needed a bit of space. She agreed it was perfect because couples who spend 24/7 with each other doesn't end well. Also, our plan was also for me to move back to New York first, and she would come a year later when she completes her job in her city.
Everything was set, perfect, and decided on. We talked about the future, kids, the whole 9 yards.
She told me she fully supported me moving back to NY to pursue my dreams and she will be with me will the end. She was unhappy living in San Francisco as well, and she wanted a change too. I moved back in January of this year and everything was well... we adapted back into long distance and she was focusing on her career and mine with school. In March, we had a little argument because she was stressed with work and I was with school so I couldn't talk to her much. A week later, she broke it off. She said we weren't the same, things changed, she was unhappy, and she needed time to figure herself out and that I should do the same.
I'm very close to her family, and her mom texts me all the time and she said to just agree and give her space because maybe that was what she needed.
I would check in every so often to see how she is doing. We miss each other but she was determined she didn't want our relationship anymore.
I gave her two months of space... I let her figure her out and I was wrapping up my spring semester. A few days ago, I learned that she moved on..... :tears:
The time we broke up, she found support in her friends, and some new friends from her work. And the girl she is with now, was one of those friends. :icon_sad:
She changed her number, and her mom told me she can't give it to me, so all that was left was me to contact her through email. I emailed her, and very long message about how I still loved her and she was the one for me, and I poured my heart out for her in a very long message. She replied but she was cold, harsh, and told me to "respect" her new relationship. She told me her new girlfriend is the most amazing person ever, she would do anything for her, choose her over anyone, and she sees her future with her. What hurt me the most was that she said "since the beginning, she's had my heart". She told me to move on, and that she was "the one" for her.

I thought I was shattered when she broke up with me in March, but I had hope that if I gave her the space she needed, she would come back...
But after yesterday and my newfound knowledge of her new relationship, I am utterly heartbroken. She was my first serious relationship and I thought she was the one for me. I even told her that and she used to tell me the same! Back when we were together, she used to tell me that I'm her world, I'm the one for her, and that whatever fight we had, to not leave her. :tears: But now all that gets turned on me?

I'm not sure how to deal... My family is not supportive, my friend's don't like her and have relationship problems on their own so they can't help me either. I'm kind of at the end of the bridge with everything now. I'm not sure what to do or feel or how to LET GO. I can't let go... I really want to and need to, but I can't seem to let it go.

Anyone out there? :tears::help: