My blood sugar level starts falling down suddenly, because of which my body starts trembling, kindly tell me what might be the issue.

Diabetes: Low blood sugar often results in a sympathetic nervous system outpouring. Sweating, feeling faint, tremulousness, anxiety, irritability...what i call the hebie-jebies. It's likely you are diabetic. If you are a known diabetic, you may be overmedicated.....or exercising too hard or eating too little for the medications you are on. DO not drive a car when feeling like this.