You drank too much water. I have done that after my four day of dry fast, drank so much water and felt terrible. After a dry fast it is important to drink water in small amounts first, then increasing it slowly, drink per thirst is the rule. Your body can go in a shock, some people have wounded up in ER.
Take care, if you are still fasting with water, break your fast the same way. Eat very little at first building it slowly.