I have pain on my left calve and minor throbbing pain on my left temple, could I be having a heart attack?

Not likely. Diabetics can have atypical signs and symptoms when experiencing a heart attack, these are not them. But if there is any doubt get checked at your doctors. Your electrolytes , lipid profile and glucose needs to be tested although by age 40 a patient should have an ekg done, but diabetics do have increased risk so it would be reasonable to have one done now. Other risks include smoking hypertensi.