Hi dragongirl.
Your Bg readings are never going to read the same just because you ate the same meal as yesterday. They will vary from day to day, hour by hour, minute by minute. Testing immediately after a previous test will also be of no benefit, test at the correct time and just take the reading as read. If you test before a meal and then at 1 and 2 hrs that will give you a good idea of what that particular meal does to your Bg levels. It will vary. I am sure there is nothing wrong with your meter, try testing with a control solution if you are worried it is faulty.
You have not had a setback, you are just expecting too much. Keep testing.
Ken.