Drinking multiple _liters_ of water in a relatively short time can cause water intoxication [1] due to the drop in relative electrolyte levels. I got it once at scout camp where, unfortunately, the medic misdiagnosed me with dehydration and had me drink a gallon of water. I ended up urinating about every ten minutes for the next 24 hours, and is one of the most unpleasant experiences I've gone through.

[1] https://en.wikipedia.org/wiki/Water_intoxication

It sounds like potentially your water/electrolyte balance was more the issue than simply saying you over consumed water. As the water consumption increases your intake of sodium, magnesium, potassium and calcium should have been equally increased. Did you do that? Did you have a blood panel done to see if you were deficient in any vitamins/minerals?

The easiest medical problem to get from drinking far too much water is hyponatremia.

https://en.wikipedia.org/wiki/Hyponatremia

I'm sure you don't have any reason to try this again, but this condition could be confirmed by a blood test.

I'm normally not going to fuss over petty downvotes but as hyponatremia can kill, perhaps you can hold off this time?