Metformin doesn't drop blood glucose by much unless you are using maximum doses.
I'm not sure why you got such a drop after porridge and honey, both are high in carbs, but some people can handle porridge well. Perhaps you are one of them? A single slice of wholemeal bread should be Ok, although there's not as much difference between wholemeal and white as you might think.
pizza base is also high in available carbs and you need to check the pizza topping label( unless it's home made.) to see the total carbohydrates count. The fresh veggies qand herbs aren't likey to be a problem.
I can't see anything obvious, but it could be a timing thing. For breakfast, you may have hit on the most active phase of the Metformin.
I couldn't eat the foods you mention without high Bgs.
Your numbers aren't bad. I would suggest you keep a detailed log for a few days and see if a pattern emerges. Each of us handles foods differently and although we all have to control carbs to some degree, we have to find our own way.
then you have to start factoring in exercise.
A newbie as motivated as you are, will find their own best way.
sorry I'm not able to ive definitive answers, but if you have more questions, ask again and I'll try
Hana