I have porridge as an occasional breakfast too, but only use 20g oats or buckwheat and 10g of milled nuts and seeds to bulk it and provide fibre. Chia or linseed give a very good bulking/thickening effect. Makes a huge bowl full that kept me full for ages, and lower carbs. I was never keeping to the super low carbs though, usually around 35-55g as a non-diabetic was good enough to keep the ketosis going.
One idea could be to try the smaller portion sizes than you are used to, and see if they are sufficient to keep you full. Another is just to allow yourself a little more time to see the effects of the whole 8 weeks.
I don’t really understand all the blood sugar values, but they are obviously both true reflections of what is happening in your body. The dawn effect means that the fasting test can be less reliable and some diabetics, including a long term poster now at maintenance called Bill, if I remember correctly, stopped using fasting blood tests at all until he lost the 15% or so and dropped below his personal visceral fat threshold to the point where the fasting bloods were normal again.