Diagnosed orthostatic hypotension. ran into walls & couldnt walk straight 24 hours, still dizzy (but not as bad) 4 days. is it serious? cardiologist?

Orthostatic hypotens: At your age to have this is not good. I would ask for a full cardiometabolic risk assessment and an Autonomic Neuropathy assessment . Both should easily be done by the cardiologist. Secondly - check for medical conditions like - diabetes, cardiac abnormalities, thyroid etc.. that may be contributing. Also if you are on any medications and supplements - they need to be re-evaluated.