Orthostatic dizziness???

When I wake up after not sleeping or lying down, everything suddenly goes dark...

Stay still in that state... or sit down for now, or squat... that's what I do.

They say there's nothing particularly wrong even when I go to the hospital...

I've fallen a couple of times... I got up quickly each time, but...ㅠㅠ I'm so embarrassed...ㅠㅠ

That's why in everyday life, I just lean on something when I feel like it... or stop for a moment with my eyes closed.

It's okay to do that for just 10 seconds...

Orthostatic dizziness... I looked it up...

Which hospital should I go to and what tests should I get done accurately in this situation???

I mentioned these symptoms during the health checkup as well... but the test results showed no issues...

Orthostatic hypotension?? I heard there's no specific medication for this..