M.,
OMGsh, you poor thing!!!
Fellow fainter here, so you have my understanding and sympathy.
I am sure the combination of getting up early/too fast...low blood sugar and dehydration was just enough to create a perfect storm of sorts...and your system simply demanded a 'reset'.
I am glad you are resting and taking it easy tonight!
Yes, definitely increase your water intake, as well as keeping your blood glucose levels even with regular snacks...
...and get up slowly in the morning to avoid a BP drop as you rise suddenly.
I hope this was a one and done episode...as I am sure it will be with those adjustments.
(((Hugs)))
S.C