Obviously - we are not your GP we don't know you or your medical history - BUT if your HbA1c test did really come back at 45 - then to put you straight onto a drug which is known to cause side effects of the 'gastric' variety, seems rather over the top, to me. Some GPs still don't suggest other ways of the patient trying to handle their new diagnosis - it may be down to the time available for GP consultations or it may be because of something else - we can't know that either.
As far as you are concerned right now - you have done the RIGHT thing in my view.
Over the weekend before you can get to see your GP again (which you absolutely need to do) educate yourself about Type 2 diabetes - the Diabetes UK Learning Zone will help you with that. It's not part of this Forum website, it's separate and you will have to register for it separately from here. Any further tips you need about reducing your consumption of carbohydrates can be got by asking questions on the forum though and the members here will all try and help you.
Good luck! 🙂