She thought she remembered how pain felt until Uriah died. Then, she found out she had forgotten everything about it.
It was stronger this time. The second death of a loved one is somehow harder than the first. Because it's more real. She already knew how bad it would be, and how much it would take her to recover from it. Looking at Uriah's body lying there, lifeless, was curse. It made her think of Will. It made her think of both. A curse she would have to live with for the rest of her life. She knew one day she' would manage to get better, to get a little over it. Because she had already gone through this pain once, but that day still felt to far ahead to ever come.
When Will died, she channeled her anger towards his killer: Tris. The most unfair thing she had ever done in her life. But in Uriah's case, there was nothing to blame or charge her anger towards. Nothing to make her feel better.