Why arent i losing weight anymre :S?

Im 8 stone 7 i lost 7 pounds of my holiday weight by goin on a healthy diet and regular exercise but now my weight isnt budgin at all. idealy i would love to get bak 6 stone 7 bt it seems impossible. any ideas? and aslo would detoxing for 3 days by jst drinkin water and not eating boost my weight lost? please help as i know im not over weight bt my BMI is something lyk 24 which is quit high as i am only 4 foot 11 thanks x