I had a sudden and severe dizzy spell today at work while at my desk. it felt like when you feel as if your falling in your sleep and you jerk awake. ?

Other symptoms: You might be describing a hypnogogic event, where you may have drifted off but not been aware of it. Have you ever been diagnosed with sleep apnea? Do you have episodes of falling asleep during the day for unexplained reasons? Please see your primary care provider, who can obtain a thorough history and perform a physical exam.