I stayed in a full board hotel. Started off sticking to plan for meals, but mus admit that I did succumb to the low-fat sweets table a few time (obviously big quark fans there - lots of flavoured quarky stuff on bits of sponge like you get in swiss roll), but could have been worse. When we were out in the evenings I just chose the drink I fancied though as my usual tipple was hard to get and really expensive (anyone would think diet coke hadn't been invented yet!!)
So, I wasn't on plan, but plan def influenced my eating choices at meal times. Lots of fruit, salad, veg, and fish where poss, and I tried to judge if the meat was lean, but that's hard to do accurately.
I did put some weight on, but it came back off quite quickly once home, back on plan, and back doing my usual exercises.
Don't stress. You'll be back on track before you know it.