Am I going to give myself diabetes? Eat a bag of candy every night

Maybe. Excessive sugar increases your risk. But that's not the only thing. It's also your lifestyle (sedentary), stress, body weight, high blood pressure, overall diet (healthy or fatty, processed foods; lots of red meat, dairy, lack of whole grains).
Overweight. Even if u dont get diabetes, so many extra calories will cause weight gain which leads to many other health problems you may suffer with later on.