Im 18 years old and went to the hospital 4-5 days ago for blurry vision, headache on one side of head, fatigue and brain fog. i found out i was severely dehydrated, they gave me 2 bags of glucose but ive still been feeling same.. im very scared?

Are headaches constant or intermittent? Are you paying attention to consistent hydration? Is there a family history of headaches? Just some of the questions which can lead to a reliable diagnosis of potential migraine, or head pain of a different etiology. Suggest you now see neurologist and address the full spectrum. No need to live with this, as intervention can turn it around.