Brief Answer:
she needs to be checked up immediately, please take her to your nearest ER..

Detailed Answer:
Hello XXXXXXX Welcome to HCM,
I've gone through your query ad understand your concern for your fiancee..

As per your description, there can several possibilities, starting from dehydration, stress, sudden drop in blood sugar (hypoglycemia); blood pressure (hypotension), syncope, over-excitement followed by some inner ear disequilibrium which attributed to the vomiting later on and several others..

It's extremely important that you take her to your nearest healthcare center/ ER of the nearest hospital to get a prompt clinical check-up without any further delay..management will depend upon the findings accordingly (it can even be simply observation, but any underlying significant pathology as mentioned should be ruled out in the first place)..

Please don't panic and get the immediate check-up done..
Try to Keep her semi-supine, if she's not fully responding/conscious, don't give her anything per orally..

Let me know how she stays in the due course..
Best Wishes

Take Care
Kind Regards

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