Dizziness and occasional blackouts

I have been going through some health issues, especially dizziness and occasional blackouts (the kind that start gradually until I have to lay down and go into semi conscious state). There are many reasons specified by doctors and consultants, it could be anxiety, panic attacks, migraine, dehydration, after ruling out other medical causes related to cardiology, neurology, thyroid, low blood, etc. My test reports are all normal, with one exception: normal sinus tachycardia, with absence of any heart diseases or abnormalities, it is not a concern.

I am enjoying starting my 30s, in good shape, exercise regularly and sleep very well.A cardiologist who examined my holter monitor and ECG told me "Dizziness may occur due to over heating and dehydration which may be occuring in your case very easily compared to others hence always keep a gatorade to boost up hydration and blood Sugar ( sudden momentary dip in blood pressure or Sugar may also cause it)"
I somehow agree with being overheated and getting dehydrated very easily because I am naturally high strung kind of person, moving here and there. I noticed that I cannot stand the heat, when I exercise, I sweat a lot, at times, almost blackout, when it is hot. However I drink a lot of water, around 3 or more litres every day. I wake up at night to visit the bathroom, sometimes I have a sudden crave for salty or sugary food, when I feel a sudden drop, unexplained dizziness, at times that snack solve the issue other times I find myself lay down my desk at work due to dizziness! However, I will leave the doctor and consultants to monitor and examine my condition. In the mean time, your opinion would be appreciated.
Anxiety and panic attacks, if present, are manageable, I would never ever use any of the psychology medications, this is all out of question, due to potential dependency. I am a dynamic and positive person, my life is going well, but at times, I honestly feel my body does not work to my advantage. I am on a short vacation, trying to relax and calm down, take it easy and slow down but my symptoms will attack out of nowhere. Tweet