STAY ACCOUNTABLE! don't give up on FS! it's a great tool and will help you get through each and every day and stay motivated to maintain your new figure!
i am always hesitant about cleanses, but as long as you're careful and two days really isn't too much, i wish you luck! i hope that you can boost your motivation and your wardrobe!
also, soda is a totally unnecessary thing- read Skinny Bitch if you need some more motivation to stay away from it (the whole book is good (although i do not live vegan at all), but you can probably find some snippets about sugar and soda from it online
for caffeine you can try tea (green or otherwise)--teavana is kind of pricey, but they have some great flavors that might satisfy your sweet tooth and give you a jolt of caffeine!