My Maltese Lady has been a diabetic for seven years. Giving insulin shots everyday is a way of life for us.
Seriously, it's no big deal. They key is to get him regulated as quickly as possible and either learn to test him yourself or take him to the vet regularly for curves.
If your vet isn't knowledgable about canine diabetes, you need to find a vet who is. This is a very treatable disease.
There is a wealth of information here:
Pets with Diabetes: Diabetes Education Index