What Causes Shivering Along With Light Headedness And Fatigue?

I feel shakey and light headed, like I am going to pass out. I have not yet passed out I eat to feel better. I have been tested for Diabetes and was told I was border line to keep peanut butter crackers with me. Is his mornal or should I get more test done.

If so, what type of tests? What happens if they come back fine again?