Why did trist do so much damage to me?

I was braum. This is NOT against vayne. I had E up. I was almost at thornmail (okay at the end I did) and trist still did so much. FH, rightous glory and thornmail wasn't enough armor??? E cockblocked nami ult GREAT :D but I still died (almost) to trist a lot. Her range isn't bad but jump means I won't be killing her anytime soon