You're not doing anything wrong and it must be unbelievably frustrating. Have you taken any 'breaks' from the diet since you started? I almost wonder if letting go and eating off plan for your holiday might shock your system into making Atkins work again - a little like Scrumbles did. But I know going off plan can be scary in terms of gain and having to get back on again.
Or, when you get back, you might try doing low carb 'up days down days' for a couple of weeks? While I was looking up the diet I noticed atkinsers using it (while still on Atkins) to break stalls - having 500 calories and 2000 calories on alternating days.
Or there's one of the Atkins recommended stall breakers - the fat fast (1000 cals a day but only tiny meals of very high fat foods) or the meat and egg diet - both only for a few days.
Of course you might find that the holiday itself is just the break you need and everything will sort itself out when you get back. But if not there are lots of options to try. You will get it sorted xx