What's wrong with me

I feel sad a lot, I feel empty, I feel heartbroken, I have a lot of self-loathing, I just don't know what I'm doing anymore. I've been crying a lot lately. It's coming up to a year since me and my ex were together and made a lot of good memories and it was carefree and I was so happy. And now I feel so reflective and nostalgic and it hurts. What's wrong with me😓