。
She was so shocked she ended up collapsing.
Literal
She [topic-は] shock [from-excess-of-のあまり] collapsed [ended-up-てしまった].
Two patterns paired: ~のあまり ('out of excess of, from too much') marks the shock as the extreme cause, while ~てしまう (here in past ~てしまった) adds the regretful 'ended up' nuance, suggesting the collapse was unintended and unfortunate. Together they paint an emotionally overwhelming moment. ~のあまり attaches to a noun describing intense emotion or strong state — ショックのあまり, 喜びのあまり (out of joy), 悲しみのあまり (out of sadness), 驚きのあまり (out of surprise) — and feels somewhat formal, common in narrative writing rather than casual chat.