I have been got reduced from overweight to normal . as i am taking 3-4 week rest. should this gap make me fat again becoz of poor metabolism inside us?

Depends: If during the rest you still take walks, remain active, eat healthy and reduce total calorie consumption you may be able to avoid gaining weight.

Normal by BMI?: You need to continue with the changes in your eating behavior that you have hopefully made, and continue with your exercise (?3-4 week rest). Weight maintenance is different from active weight loss. Your weight may fluctuate a bit.