There's two ways to feel heartbreak: emotionally and physically. You can feel one or you can feel both. There is some science to "physical" heart break, but I won't get into it. It has more to do with chemicals, hormones, stress, and how going through heartbreak causes your body to think there's something wrong so symptoms include heightened weight loss or weight gain. Some people say they feel a literal chest pain. I felt pain in my gut, like that butterfly nervous feeling. I would get sick thinking about the breakups.
But emotional heartbreak is different for every one I think. There's a process, like with grieving a loss. You''l feel it all. Depression, anger, self-deprecation, anxiety, loneliness, and confusion. I think, for me personally, the worst part of heartbreak is I question my identity. I've been in long relationships where when I come out of them, I feel like a huge part of myself is gone and won't come back or be filled. That takes lots of time and LOTS of introspection to get over. And it hurts like hell wondering if I'll ever be loved or love again. It's scary. I can't even express it in words.
I will say, the older you get, the more relationships you have, and the more you learn about yourself, it can either get easier or it can get harder - especially when you truly care about someone and that ends. It all depends on you. If you take every break up very personally, it will hurt you more than if you appreciate the time you had with that person, learn from it, and move onto the next until you find the person you want to be with forever. We all change and grow. We all put power into things.
Heartbreak is sooo difficult to describe, but honestly, such a crucial thing to experience as a human being. 