I know how frustrating it is when you feel like you´re doing everything right and the scale doesn´t move as fast as you´d like. But you lost 1.7 kg in your first week, that´s great! And you´re sticking to your planned calories, that´s also great! Not losing visible weight for a couple of days is not a rarity. Sometimes it´s hormonal (I gain about a kilo before every period, which promptly disappears again once the floodgates open), sometimes it´s to do with the amount of salt we eat (salt bloats), or unaccustomed exercise... and sometimes there doesn´t seem to be a real reason. Give it a week or two and see what happens.