Diabetes is one of the silient illness that don't show any visable signs, unless you you have some of the complecations that are noticable. A lot of non diabetics don't know about the illness either and don't unstand that giving sweets etc can be bad for us and its hard to refuse them with out them wondering whats going on.
Meters are not a problem, as most manufactures will give you one free like Abbott medisense, Bayer, and numerous others, these meters will come with 10 tests strips to test the meter out, and if you phone one of them up you will normally get one by return of post.
The problem for some is getting the test strips on perscription, as some people have had them refused or have limited supplies of them on persciption.
If your practice won't supply you a meter or strips on persciption there are a few low cost meters / strips around, like the SD code free and Supercheck2 meters. The Supercheck2 strips are around £8-49 for 50 and £4-50 for 200 lancents, these are a lot cheaper than the big brand names as their strips can be £25 + for 50 strips.
Getting a meter at least will give you are starting point to as to what your Blood sugar is like and you can then go back to your GP and at least show how high or low you numbers are. Testing first thing in the morning will give you a fasting reading (aasuming you have had no snacks in the night). Then test again 2 hours after a meal to see what you are peaking at. Though different foods will cause higher or lower peaks, for me one food that sends my suger sky high is white bread.
You can then show people that don't believe that you have diabetes your results and explain to them what normal readings should be hand the higher the numbers the more damage it does like it can affect the nerves and eyes typically with eyes if sugers go high it can lead to blured vision.
If youve not already done so, as you are taking metformin, you can apply for a perscription exemption certifecate.