the last 3 weeks

diet:
slim fast shake breakfast
slim fast shake lunch
low calorie meal dinner
snacks either rice cakes or cuccumber/carrot sticks
calories arround 700 a day.

exercise
25 mins on either treadmill/step machine/bike every day

i have two toddlers so constantly cleaning, running arround for them

im 21, 5ft3 and currently 12st. size 14

like i said ive been doing this for 3 weeks. i havent slipped at all, and im really enjoying it and feel much better, healthier....

so why after 3 weeks have i lost 1 pound? im so confused and feel totaly depressed that all my hard work, desperately ingnoring cravings for takeaways, aches and pains from the exercise is wasted.

im drinking 2 litres of water a day. where am i going wrong? the worst thing to pass my lips in 3 weeks was a small slice of pizza, but i exercised all night to work it off

help because i need motavation! my goal is to lose 2 stone in 3 months.