First of all, congratulations on your loss so far! That's a huge accomplishment and you should be very proud of yourself.
It seems like you should spend more time reading about nutrition in general (books and/or health sites) and the experiences people have dieting (this site).
It is completely normal for your weight to go up during the day. It would be rather shocking if it did not. Most people on this siteweigh themselves in the morning (if they weigh) in order to get the most consistent number. It is also perfectly normal for the scale to go up some days for no apparent reason. You just have to keep the trend moving down.
It is also normal for weight loss to start off much more quickly then slow down as time goes on. You lost 5 kg (= 11 pounds) in 2 months. That's a very nice rate of weight loss. The initial rate you were losing was unsustainable.
You should probably read about fruit juice. It sounds like you might be drinking a lot of that (and eating a lot of fruit). Fruit juice is very high in sugar without any fiber. You might want to think about eating a more balanced diet that limits juices.
Again, I think you really need to learn more about both nutrition and the experiences people have dieting, but you've done a great job already on your weight loss!
Hoping to earn the user name NoYoyoMa...