could anyone understand?

I feel silly for crying, and I wonder if there's anyone who could understand...
My ex has a new girlfriend. Last night I went to a party and for the first time I saw them together... I'm talking really close together. Inseparable. The way he and I used to be. Memories came back to me. It hurt so deeply. I was still in love with him. But this is the silly part: we've been broken up for years. How could I still be in love? How can I still be thinking about him? What we had was deep and lasted forever, and because of that, I thought we'd always be together. It's a broken dream. And no matter how many songs I write or how many tears I shed, the pain is still there.
I'm afraid to go into an episode and I so desperately need support from those who understand. I have a friend who also has a mood disorder but I really can't talk to any of my friends about this. I want to present a strong front. And I don't want anyone to know that I'm really losing it. My friends talk. They might mean well. But word gets out.
I feel stuck...and alone.