FAF, I'm late in joining this, but I wanted to wish you well, and hope your granddaugher is okay.
About your diet/lifestyle, don't panic - stick with Atkins, and you will make it! You are a touch shorter than me, but I still weigh more, and I don't think I've got "tons of blubber". You've already gotten down to your pre-holiday weight, now the rest is all new loss!
I recently went on a cruise, and someone there told me that I wouldn't gain weight from all the food available, but the sea air would make my clothes shrink! When you're on holiday, you eat too much, drink too much, and don't worry about exercise. Usually, you eat more salt than normal and not enough water. All these things put weight on quickly, and when you get home, it's easy to get it under control.
The people on this board are so nice! Keep coming to them if you get stuck, they'll help out!
Best of luck
Seraphine xx