It's today, isn't it? So OP should be sorted by now!
But Rainbow -
"To the posters who are saying that it is short notice and they would have to go to the shop to get stuff for a packed lunch. Are you really suggesting that you have nothing in to make a lunch, no bread, cheese, cold meat, jam or whatever, couldn't rustle up a few crackers and cheese, a bit of fruit and a biscuit or pack of crisps or a yogurt from their fridge and cupboards, I find that more incredible than the ones who think it is rude to ask for a packed lunch."
I don't have children, but no, I don't. I don't have sandwiches as I'm gluten intolerant, I'm trying to avoid bread. I tend to cook lunch - scrambled egg usually - or I'm at work so it's catered or I buy something. I have crisps, probably, but not fruit (I'm not at home enough to eat it, it just goes off).
I don't think I'm that unusual - my friend has two kids and I babysat last night, she has no packed lunch stuff in either as it's half term and they've grazed on it all already. They knew that if they ate it all early in the week, they wouldn't have anything else bought. Again, they've meal-planned cooked lunches and dinners for the week.
On the right day, I'd make an effort to go to a shop on the way home and pick stuff up and it'd be no problem - but I leave at 6am three days a week, and don't get home 'til 10pm. There's nothing open around here then. My routine means I just eat out, but that wouldn't help with one days notice. I'd probably borrow from neighbours/friends if the situation did arise for me, but not everyone would have that option - so I was just saying that OP might need to take some things, if there are parents who couldn't prepare a packed lunch at short late notice.
I don't think it's that unusual but maybe I am!