I get low grade fevers at night only. Fatigue, dizziness, tired, rapid heartbeat. I have been diagnosed with prediabetes, high cholostoral and anemia?

Further tests! Your diagnoses don't explain your symptoms. Since it's not normal to have nighttime fevers, you need further testing. Please see your doc again and find out why you are sick. If you aren't satisfied with the answer, consider getting a second opinion.