My understanding of T2D is that it stems from an original high-carbohydrate intolerance, which leads to high levels of insulin (made by your pancreas) to deal with the high levels of blood glucose (caused by lots of carbs and sugars, which your body just cannot handle), which in turn causes your body to turn off to the signals to tidy away the glucose and get your level at the desired one - that 'turned off signal' is called insulin resistance. You have early signs of insulin resistance. Taking medication will not help your body regain insulin sensitivity, is my understanding. You need to help your body deal with the insulin resistance. Your doctor is actually doing you a big favour by telling you to deal with that, although it is a shame he or she did not spell it out to you. This is where lowering the amount of carbs you eat comes in, and absolutely lowering the amount of added sugars, and processed (ie factory made) food. Trans fats and sugars are the enemy of your health.
Yes, increasing activity levels will help your body deal with the glucose in your blood, and any stored fat you have, to get your blood sugars to a normal level (your goal I take it). Your liver is not at the moment badly affected - this I can see by your Fasting Blood Glucose level - which I would kill my first born to get again! (Not really! But you see what I mean.) What you have is a high post-meal blood glucose level - and this does indeed tell you your body is beginning to have a hard time with the high levels of carbs and sugar it is having to deal with. You can see, then, why diabetics and pre-diabetics tell you at absolute bottom line level - lower the amount of carbs/sugars your body has to deal with. (This is the 'diet' component.) And yeah - more activity will get those excess post meal sugar levels you have now into your cells which is where it should be, as long as the cells aren't overloaded. What you absolutely don't want is for the excess sugars from too many dietary carbs and sugars to end up stored around your liver and pancreas - because then you will join folk here in the T2D forum.
Please, anyone, if I am wrong in what I am saying - do tell me! (And Abri), but metformin will aid you if your liver finally gives up the ghost and switches off the signals due to being overloaded. (I am hoping that liver health can be regained, but this is something I still have yet to see.) Metformin will then attend to one of the switches, and help the liver not excrete blood glucose into your system due to hormone messages, when you already have plenty of glucose floating around in there. (I, like many diabetics, have this issues, which is called 'the dawn phenomenon' or 'liver dumps', and is reflected in that morning fasting blood glucose you mentioned, and yours is normal. This is what is meant by 'wrong signaling'.)
This is why your doctor wants you to lower the amount of blood sugar you have in the first place, and not go on medication.
By the way, I am sorry that you have discovered that you cannot consume large amounts of carbohydrates and sugars without the organs of your body crying out in anguish! (That's my dramatic way of describing it.) You have my sympathy, absolutely. But all the prediabetics and T2 diabetics in here have the same issue. You can still have a great life and fun with food with lowered carbohydrates, I promise. But you won't be like your family and friends who didn't and don't become pre-diabetic in the first place.