I am awakend from sleep thinking i'm hearing someone is knocking at the door and it's my heart racing is that normal? i am diabetic.

This : This is called tachycardia (fast heart rate). This is not normal and is something that needs to be investigated right away. Common causes of tachycardia include: heart disease heart arrhythmia high blood pressure smoking fever increased alcohol or caffeine intake medication side effect electrolyte imbalance thyroid disorder etc. The bottom line is to have a medical evaluation by your primary care provider. Best of luck.

No: Are you having dizziness/vertigo when standing after lying down or being sitting? Diarrheas? Do you have tingling/numbness feet? Heart burn? If yes, you may have diabetic induced autonomic dysfunction as cause of your problems. Consult your primary care physician.