I've read about the connection between cannabis and hypoglycemia (low blood sugar) before, but not in any sort of medical study or publication, just in anecdotal reports. I think that would be a good idea to test yourself a few more times. If it simply knocks your blood glucose down a few points, that's easy enough to make adjustments for through your diet both before and after you smoke, at least as long as the lows aren't dramamtic and don't leave you feeling shaky and out of sorts. I've read on more than one occasion that cannabis isn't a good mix with diabetes, but I know one thing for sure. It's a far better mix with diabetes than alcohol. Now that's a disastrous combination.