If you weight 48kg after drinking 1L of water, that means you weight less than 48! (1L = 1kg!). Anyway, there can be weight variations from day to day according to the number of hours you slept, for body temperature and so on... So there's a great chance you're actually under 48. :)Congratulations for not gaining anyway! Xx
Wow, congratulations. And Queenie's right, if you drunk loads of water just before you probably weigh less than that.