Welcome to the Triple Digits Club! You are off to a great start!
Keep up the good work and check in as often as you can to "recharge" your motivation.

Results like yours help keep the rest of us motivated.

Again, welcome!

BrewWa

PS Forgot to answer your questions.

Being tired is normal the first few days. It will pass.

I personally avoid eating late at night. After dinner, I'm usually not hungery.

yes you need potassium (amount escapes me now).

As for losing 21 lbs, see Kenny's Journal. He's lost 50 lbs in 3 months. As long as you are getting your nutrition, you should be OK.

Cheers!