Ok you need to stay off the scales. If youre going to weigh in every day you need to take the result basically with a pinch of salt and not let it get to you. Otherwise, as you see you get dermoralised. Weigh in once a week and leave it at that. I did mid week weigh ins at the start and found sometimes I lost nothing in the first half of the week and then might lose 4 in the second half - or vice versa.
Bottom line is when youre having 600 cals a day, you cant NOT lose weight.... weigh in once a week for the sake of your sanity