Veil - Best advice I can give you is to hang in there and take it one day at a time. Use the Anita moves if you can't keep up with Natalie. Believe me, it's still a good workout. I also did not do the challenge 30 days straight. I did 6 days a week with one day off.
I normally have a apple before I drive home from work so that when I get ready to do the workout I won't be famished. Nothing worse than working out while your tummy is rumbling. After my workout it's pretty much time for dinner.
Good Luck!
KimmyKitty -
to the Challenge. If you ordered all three that means you'll be doing the 30 Day SlimDown one day! Much harder than 30 Day Shred. Not trying to scare you, but it is.
rainydays - I don't recall any tricep kickbacks but I do recall the static lunge w/ bicep curl. But at any rate, when I did Level 1 last night, I feel much stronger and wasn't as winded this time around.
MrsDeenz - You'll do push-ups in Level 1 and 2 and planks in Level 2 and 3 which should help you get stronger, so eventually you should be able to do them in no time without trembling. (And if you do 30-Shred a second time around, you'll really see a difference.)