Metformin has no effect - advice please

I was diagnosed about 5 weeks ago. GP assumes that I'm Type 2 due to my age although no tests have been performed to confirm this. My BG was 24.6 but Hba1c was only 10. I had been unwell for about 5 weeks prior to going to GP with suspicion that I was diabetic.

I was started on Metformin as I was already following a healthy diet, history of Type 1 diabetes in family and husband type 2 diabetic. A week after starting metformin I'd managed to reduce my BG to 18 but GP sent me to hospital as he thought I was aciodic, they thought I was probably just eating too few carbs - had cut out all starchy carbs, although they told me that the tests they'd carried out initially were inconclusive and that I might or might not be acidoic, a further test on the ward suggested that it was safe to allow me to return home.

After 5 weeks on metformin (now taking 1g morning and evening) there is very little change in my BG. I can get it down to around 16 to 18 by exercising frequently and following a very low carb diet, but it regularly jumps up to 25+ if I eat starchy carbs or don't exercise enough.

Have to go and see GP tomorrow, says he'll check for infection and discuss change of medication. He confirms that they are only assuming that I'm type 2 and that there is still a possibility that I'm type 1. Any advice on how to proceed and what is likely to happen would be appreciated. Should metfomin have had some effect by now?

Thanks for the replies. Saw GP om Tuesday. BG was 20.5. My husband asked about c-peptide test but GP felt that I was almost certainly type 2 otherwise I'd be in far more trouble by now and at the age of 49 it would be very unusual if I was Type 1. Other than starting insulin sooner rather than trying all different medications first, is there any advantage to knowing if it's type 1 or type 2? My symptoms are less acute than when I was diagnosed although this isn't reflected in BG results. He's started me on Gliclazide as well as Metformin and said a GP will phone me next week to see if there is any improvement. At the moment BG is still rising slightly each day and I'm so tired I fall asleep every time I sit down.

Thanks for responses. In fairness to my GP, he freely admits that he's not a diabetic specialist and at every point since dx he's sought advice on treatment. GP would have preferred admission to hospital on dx, but I have a child on the autistic spectrum who needs 24 hr care and is educated from home so did not want admission to hospital when diagnosed. He sought advice from an Endocrine Specialist at the hospital and followed that advice. A week later when he discovered loads of ketones he sent me straight to the hospital. They kept me 9 hours and then discharged me with instructions for GP to follow. On Tuesday he again sought advice from a diabetic specialist before proceeding. I do have to say that our local hospital does have a terrible reputation and is always in the news for negligence, but that's hardly the GP's fault. He has also told me to phone him or go straight to A&E if I start being sick or have stomach pains.

The gliclazide does seem to be lowering my BG slightly and today I haven't fallen asleep so I'm hoping that will be the answer. I also had my retinopathy screening yesterday and the good news is that everything was fine.