Noooooooooooo!! Oh sweetie...
Well, come on, chin up - you now know how rubbish you feel so take stock of that, and don't do it again. That 'light headed' feeling was probably to do with you going into ketosis (assuming you've been doing it a few days? When did you start?) Now you've eaten that amount of sugar, you will be back to square one and will have to go through it all again.
It sucks, but it is worth it when you get through it and your energy kicks in, so perservere!!
If you've only just started, then I would really re-evaluate your reasons for doing this, because if you aren't fired up now, then you won't last two seconds weeks/months down the line when people say you are looking good and 'just a bit won't hurt'...
Carbs are addictive and evil, so I really do sympathise, but to do Atkins you've got to be prepared to acknowledge that and stick two fingers up to them and tell them you won't give in.
Good luck getting back into it - we are here for you if you have a week moment again x