Hi. Many times when we are Just enter into the stage of sleep or Just prior to being awakening may feel that we are awake but still unable to move our body. This phenomenon is quite normal, because the sleep is not a Deep sleep ,but the Brain activity has slowed down causing the limbs to loose there power. But It should not be occurring too frequently i.e almost daily, otherwise its just fine and a normal thing . But feeling giddiness during walking may be symptom of some under lying problem. And the problem may be in the ear which controls body's balance or may be in the brain. So for these problems its better you take consultation with a neurologist