Hello dear, The sensation of dizziness on assuming a particular head posture can be attributed to pathology in the Vestibular Apparatus in inner ear (it is associated with maintenance of body posture & balance) most probably Benign Paroxysmal Positional Vertigo. Symptomatic relief can be obtained with intake of Vestibular sedatives like Betahistine or Cinnarizine preparations (to be taken only under the guidance of a Physician). So, kindly consult your Physician/ ENT Specialist & get a complete clinical examination done. Investigations like complete blood count, estimation of blood pressure, blood sugar levels, serum electrolytes & vestibular function tests will be required to rule out any pathological cause for the symptoms. There is no need to worry, you will be fine. Till then, maintain adequate hydration & proper nutrition status and avoid stress. And also take precautions of getting up from bed slowly & avoid sudden head movements. Wishing you a Good Health. Take care.