Testing your blood sugar won't tell you anything about PCOS. It will tell you if you are a diabetic or pre-diabetic. In order to understand what is going on with PCOS, you need to find out what your insulin levels are doing -- both fasting and with a GTT. A competent endo will also run LH/FSH, testosterone, DHEAS, prolactin, lipids, and a thyroid panel. If you haven't seen an endo with experience treating PCOS, and your last bloodwork was run 5 years ago by a GP, you really have no idea what is going on with your body hormonally, which could very easily be the primary reason for the struggle.
When you say the medicine isn't working, what do you mean? Aside from weight gain/difficulty losing weight, other symptoms of PCOS would be long/irregular cycles, hirsuitism, acne, depression/mood issues, and thinning hair. Are you experiencing any of these symptoms?