I've put my self on a diet and its to loose 10kgs in 7days?

i only need to loose 5kgs but i wanna be a lil underweight so its not such a big deal if i gain a lil but all you get to eat is soup the same soup all day for 7 days and water and on the odd day u can have a gl of skim milk or some thing and im findin it hard to stick to the det i did it in the past on the 2nd day i had lost 2kgs but i quit its so hard to stick what can i do to desract my self