"Ik voel me opeens zo duizelig."
Translation:I suddenly feel so dizzy.
I think the voice over at normal speed does not pronunce the word 'opeens' at all. The slower voice over does.
Very is not a correct translation, since it would be a translation of 'heel duizelig'. Meanwhile, the word 'so' in English can be used in this manner: 'that's so beautiful', 'you're so dead', or 'I'm so sick today'
The English sentence might be unusual, but it's not wrong, and it's closer to the Dutch original than if you were to replace it with very.