I have diabetes and a calcium level of 11 in my blood. is that serious?

Not normal: Hi. Unless you have severe kidney disease from your diabetes, your calcium of 11.0 has NOTHING to do with your diabetes. That's a high calcium and likely to be symptomatic. The first thing to do is repeat it with an ionized calcium and PTH. If reproducible and PTH is high, get 24-hour urine calcium. Better see an endocrinologist. If PTH is suppressed, need further work up (calcitriol, SPEP, PTHrP)