Is this normal?

So I did a Water Fast for 1-2 days and lost 8-7 pounds is this normal? I mean I am morbidly obese and young (16 yrs old) could these be factors in it? Is that much weight ok to lose within 1 to 2 days? Also another question I have is do I have to take any supplements I wasn’t taking anything on this Water Fast just water with lemon juice should I be taking anything on like a 1 week water fast?