The normal reference range for monocytes is 3- 10% 11.5 is slightly elevated and could simply mean that you may have inflammation present. Your doctor should check you again in a week to see if the monocyte levels have increased or decreased. As of right now... 11.5 is only slightly elevated and nothing to worry about.
I am not a doctor, but if you are concerned your doctor should have explained what it meant. And if he didn't, remember he works for you. Here is a website that I hope will help you too. Best wishes to you.