I have fasted first significant periods for 5+ years and many times I’ve broken fasts with extremely carb heavy meals. I also participate in a number of fasting social networks (both on and offline). I am just saying you might want to investigate this further as a (relatively) short 48 hour fast, broken with a carb heavy meal, should not have led to what you are describing. Something seems very unique about this and shouldn’t act as a deterrent to others. For you personally, if it is related to the fast, you might want to try Snake Juice [0] which you can make at home and keeps your electrolytes up without the sugar of Gatorade and others.
For anyone interested, Dr Jason Fung’s book [1] is an excellent primer on how to fast safely. On reddit /r/fasting and /r/intermittentfasting and /r/fastingscience are great resources for more info.
[0] For 2L water:
1tsp potassium chloride (NoSalt / SaltFree)
1/2tsp Himalayan pink salt
1tsp sodium bicarbonate (Red Mill. Not processed Arm & Hammer)
1/2tsp magnesium sulphate (Epsom Salt. West Point. Must be Food Grade)
[1] https://www.goodreads.com/book/show/32670670