Вопрос по английскому языку. Как на английском будет- я даже немного растерялся от увиденного

Контекстику бы для точности, ведь растерялся можно передать кучей слов, в зависимости от оттенка значения.
to be confused // nonplussed // abashed // disconcerted // perplexed // bewilded // puzzled
to be at one's wits' end, to be at a loss

Но все они чуть отличаются, например:

If you are abashed, you feel embarrassed and ashamed.
He seemed both abashed and secretly delighted at Dan's gift.

If you are bewildered, you are very confused and cannot understand something or decide what you should do. Some shoppers looked bewildered by the sheer variety of goods on offer.

If you are perplexed, you feel confused and slightly worried by something because you do not understand it. She is perplexed about what to do for her daughter...

If you are nonplussed, you feel confused and unsure how to react. She expected him to ask for a scotch and was rather nonplussed when he asked her to mix him a martini and lemonade.

at a loss 1) puzzled or uncertain what to think, say, or do: [with infinitive] she became popular, and was at a loss to know why

Я бы взяла nonplussed, оно самое нейтральное, на мой взгляд
What I saw made me feel rather nonplussed // ...(здесь уже можете подобрать более подходящий синоним)
Можно и так:
What I saw drove (или же reduced, put) me to a nonpluss.
I was at a loss with what I saw.
I was even a little bit disconcerted with what I saw.
Если это те чувства, которые он испытал, так сказать, на месте некого происшествия, то есть в тот момент, когда что-то увидел, то Past Perfect здесь лучше не брать.

I even got a bit confused because of what I had seen.