You have dizziness
which is a vague symptom since I do not know your medical history. Dizziness can be caused by a number of different conditions. It is important to clarify with your doctor
whether you have dizziness or vertigo. Vertigo is when the room is spinning around you when you are sitting or standing still. Dizziness is lightheadedness without the spinning. Some common causes of dizziness are orthostatic hypotension or arrhythmia or vision changes. Orthostatic hypotension occurs when you change positions form a sitting to standing or walking position. Normally, blood pressures decreases when you stand up but your heart compensates. If your heart doesn't compensate adequately, you have orthostatic hypotension. It can be caused by dehydration or even blood loss. An arrhythmia is an abnormal heart rhythm such a atrial fibrillation. It can cause the heart to beat very fast and this decreases the blood flow to the body including your brain. Also, recent changes in vision can cause dizziness if not corrected. You are an older gentlemen who could have other medical illness that are contributing to your dizziness. It is difficult to know what it is at this point. You should make an appointment with your primary care doctor
as soon as you can.