I believe I know what type of headache this is most likely but would like to ask you a couple of more questions.
Do you feel this headache on the left side, right side or in the middle of your head? Do you have any tearing of one eye, runny nose, drooping eyelid or swelling around one eye with the headache? What migraine medications have you tried?
The fact that the headache is in the middle and very sharp in quality indicates this is not a migraine and I do not think this is related to your diabetes.
This may be what is known as trigeminal neuralgia, which is due to irritation of one of the nerves that goes to the face/forehead. This can usually be prevented by medications such as carbamazepine. However, it would be more typical for trigeminal neuralgia to be either on he left or the right side rather than in the middle. Less likely, this is a variant of a cluster headaches, which tend to occur around the same time every day but also generally are on one side or the other and usually go with eye tearing/dropping/runny nose/nasal congestion. These also may be treated with particular medications.
Because of the somewhat unusual nature of your headache, it my be best to discuss this with your doctor. An MRI of the brain and basic bloodwork such as a vitamin B12 level would probably be in order to make sure that your headaches are not due to anything else such as a structural problem in the brain or vitamin deficiency.