Hi Lewis, don't be afraid to let people know you have diabetes. It's not something you should feel ashamed or embarrassed about - it's not your fault, but it is something that you will need to pay close attention to and this will be helped if those around you who love and care for you know what challenges you face.
Unfortunately, the media paints a very negative picture of diabetes, insinuating that it is down to poor diet and lifestyle choices, and this is why many people feel embarrased or guilty about their diagnosis. There are far more people who lead dreadfully unhealthy lives who don't get diabetes, and you don't have to lead an unhealthy life to get it.
Once you have it out in the open you can educate people about diabetes, and I think you will discover that many diabetics lead far healthier lives than their non-diabetic friends and relatives.