Hi! I had gone through your question and I understand your concern . Yes these symtoms are caused by orthostatic or postural hypotension ( orthostatic blood pressure) It happens when you stand up - gravity makes the blood to pool in your legs so the heart has less blood to pump - low blood pressure ( means less blood will go in your brain and the other part of the body ) . Normally our body has natyral process to fix the hypotension problems in these process ( in heart , nervous system , metabolic problem ) cause orthostatic hypotension. The important thing is to find the main cause of the orthostatic hypotension here are some that may cause : - Dehydration ( diarrhea, vomiting , fever , not drinking enough water . - Heart problem :Slow heart rate (bradychardia ), heart valvue problems ) -endocrine problem :low blood sugar ( hypoglicemia ), Addison s dissease . -Nervous system disorder . If I were you treating doctor I would check your heart , ( ECG , Ultrasound ) do some blood test to check your blood sugar . You have to do an appointment with your doctor for that . Meanwhile drink plenty of water . Wish these help! If you have any additional question please feel free to ask me .