Try try again

You know what they say, if you fail, try try again...but god damn it! It's so hard!
Lately I have not been able to control myself much.
I've been baking cakes, and also eating it. I didn't eat the whole cake, but I shouldn't eat any cake all together! It's tough living off 1100 kalories a day. Sometimes you just really crave something with more calories, or maybe just dying to eat pizza... which should be fine, once in a while. Only not fine when you're trying to get rid of the last 2 -3 kilos. It's like my whole body is fighting against me, giving me signals of craving for cakes, icecream, chocolate, candies etc. when I should be concentrating on loosing weight and thus eating a strict diet of healthy low calorie low carb food.
Why is it that my head is all about cake? I try so hard to stay away from anything fattening, anything high on calories, and try to eat tasty yet healthy food, which I really like! It's not like I am dieting on powder shakes or crazy stuff like that, I am actually eating real human food, I just don't go for rice, pasta, or bread. I usually eat a lot of veggies, meat and sometimes fruit.
I try so hard to stay on the right path, yet I stray so easily! I am so easily drawn off my path of enlightenment, by things like brunch, birthday parties, going out for a 3 course dinner, cakes, and chocolate!
Yesterday I went out to celebrate the birthday of my younger sister, by inviting her out on brunch and a movie afterwards. I had WAY too many calories and gained like 600grams just by that.
I hate it, why do I gain so easily, it's so frustrating, like nothing you can ever imagine.
I try really hard to stay on 1100 kalories, but when I have been out training, I have to eat more, or I get a headache..well maybe I just expect too much in too short a time.
I want the weightloss to happen FAST, I want to be ready for a no calorie count life in no time..but it's just not that easy.
I seem to be stuck around 60-61kilos.. and I just can't seem to break free from this, going on 2 -3 days where I stick to my diet, and then it's going out for dinner, or making a quick meal, or going out for brunch to celebrate one thing or another. and back up goes the scale! V_V
I don't know how to break free of this evil circle! Damn it!