As you already seem to realize, that is just not a reasonable goal to want to lose so much in so short a time--not to mention, it's not healthy nor safe. I can only recommend that you set a realistic goal (say 2 pounds per week) and work toward that instead of setting yourself up for failure.
Wishing you all the best.
"I am only one, but I am one. I cannot do everything, but I can do something. And I will not let what I cannot do interfere with what I can do." Edward Everett Hale