I hope you are recovering from your flu. Iv had a on/off thing for a couple of days which is wouldnt usually get. It presents in a headache and increased body temp (regardless of what iv been doing/wearing etc) and you feel nackered. Though it can pass after a couple hours.
Great work losing that weight already. Dont worry about the odd slip, its a learning curve. Especially in the case of your evening class. Tupperware my friend, learn to love it.
If I can make a suggestion, dont worry too much about the scale. You are in your first week so its a great time to get out the tape measure and measure your chest, waist, butt, arms, legs. Maybe even a before and after pic. Thats what I recommend to my clients and it works. Water retention can change daily, waist circumference, not so much.
It isn't the mountains ahead that wear you out....Its the grain of sand in your shoe.