I haven't had this problem with Mircette, and I've been on it for a year. That isn't to say that the Mircette isn't causing it though. I always emphasize that everyone reacts differently to every pill. When was the last time that you were checked for IR? You may want to be rechecked if it's been a few years--even if you didn't have it last time, it can develop. Also, since you're eating more on the Mircette, what kinds of things are you eating? If your eating habits have changed drastically, your body may just be trying to adjust. You may want to call your doctor to ask if s/he has any insight as to what it could be.
I also found these studies on Mircette and other desogestrel BCP's:
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum.
From those abstracts I would guess that it's possible that Mircette could alter your glucose tolerance, but unlikely that this would be a drastic change like you're experiencing.