Awww Slinky, don't worry, all of us have low times. It's a big change to come off food altogether. I always keep some low carb things in the fridge in case I have a day when I need to eat something other than packs.
You could also consider working solution, so that each day you plan a low carb meal.
If you're really struggling with it, you might want to think about one of the more conventional diets, that lets you choose the food to eat.
If you can, I would go with the low carb thing tonight and then see how you feel in the morning.
Don't beat yourself up about it, just see how you get on tonight (and at least you didn't dial the unmentionable straightaway!)
Take care of yourself, and do something nice to help you relax. Maybe a nice bath, or paint your nails,
Good luck xx