Hi Lucy! It's nonsense to say that if it starts high it will be high all day. Also nonsense to say that metformin will take care of it. Metformin will help a little, but it's the weight loss (lowering insulin resistance) and diet (lowering the blood glucose response to food) that will help you.
Fasting BG's always seem to be the last to come down when we reduce carbs to control BGs, so don't get over concerned. The Dawn phenomenon seems stronger when we're first diagnosed and for some time after as well. Just stick to your carb routine. It helped my morning levels a little by making sure I ate NOTHING two hours before bed. If you go to bed with raised levels, we don't then do much (well, much of the time!) to lower them. An endocrinologist told me that T2's on diet only/metformin tend to "straight line" during the night unless we go to bed with very high levels. Also worth a ten minute only fairly vigorous exercise 1 hour after the evening meal (could be just walking up and down stairs) to get the peak level down quicker and further.
Personally, I'd ignore fasting levels for now and stick to testing two hours after eating. If you're not below 7.8 then, cut out some of the carbs in that meal next time.