I CANNOT BELIEVE...

Yesterday...I never come school and today i come back school le my friends told me that i I becomed thinner and i had won a VOUCHER!!
But others of my family member all say me fat liaos lor....Impossible i become thinner right?....
Actually i am exercising but i just can't make myself become thinner....
Help me if you can .... I try to eat lesser i try to exercise .. and all things able to let me be thinner but still can't ...
PLEASE i WANNA SOMEBODY TO HELP ME......