Sweeti, don't worry about being absolutely 100%. I mean, that sounds bad but count your calories and make sure you're in deficit every day. Everyone's needs are different so I think that the one size fits all approach doesn't necessarily work well. I found a website that works out precisely how many calories you need every day to lose 2lb a week, they base it on your height, age, weight and activity levels. It's
Weight Loss Resources if you're interested.
Also, with me it took about a week to really get into the right mindset with this diet. So just give it time, take it day by day and do your best!
What finally clicked with me was when I thought, "Today is the day I start. Time will pass anyway, and I can choose to do what I want with that time: make choices that will lead to weight gain, or make choices that will lead me to a happier and healthier body. But the time to make those choices is NOW, not tomorrow or next week."
Well done for sticking at it and keep trying those different packs, they really do all taste completely different so it's worth trying as many as you can to see which you like and don't like.