My mom is 67. For past 4-5 days she is feeling weakness and giddiness only in the mornings an hour after waking up. It last for 2-3 hrs in which she feels weak and unsteady while walking due to lightheaded ness. What is this? After that she is better and quite ok in the evenings. She has thyroid and had her gall bladder removed 10 yrs back. She has been healthy till now. Her ECG and hemoglobin was normal when checked 3 months back. Thanks.