Try some caffeine.
You just need to drink extra water but it may help you with the brain fog. The brain fog should go away once your brain starts using ketones for fuel instead of carbs. Make sure you are eating all 4 cups of vegetables a day. Your brain still gets 25% of it fuel from carbs and 75% from ketones.
... I did try having celery to get me rolling but didn't work and some brocolli. I'll be better. I obssesed over what I had done all last night, and from what I found out, I will be out of wack (not loosing fat) for a day or 2. I tell you, it so was not worth the guilt and the trauma to my being.