I've experimented with a few IF setups, and settled on an 18-6 Fast/Feast with just couple pulses of casein hydro during the day. Not sure what would cause the brain fog specifically, but I noticed the transition was very easy for me the second time I experimented with IF after doing a month of very low carb breakfasts, but eating at least a few hours after waking. Also a piece of fruit during the day, like the warrior diet, can help a lot. Also, as Amonero mentioned, lots of green tea is great, but if you want to sustain this, you might want to go easy on the stims.
I'm a teacher as well, so this way of eating has fit really well with my schedule. How are you handling all that food in the feasting window? I've never tried this for bulking, but I'm full at night when cutting, and am having trouble imaging getting in everything at night.