Well done!
If you want to come off the meds, just ask the nurse. If she says no, ask her why. If she says because they are the reason you have normalised your BS levels, tell her it is your diet that has done this, not the Metformin, and ask her to let you have a period of time without the meds to see what happens. She can't force you to take them. All she can do is advise and give you a prescription.