Hello @kizu, I can't imagine the frustration you have been put through trying to get someone to listen and find a treatment that helps. Some of the symptoms you mentioned sound a little like Orthostatic hypotension (postural hypotension). Mayo Clinic has some information here on the condition - https://www.mayoclinic.org/diseases-conditions/orthostatic-hypotension/symptoms-causes/syc-20352548.

You also mentioned having mottled skin. Here's some information that may offer some suggestions that help - Causes and treatment for mottled skin: https://www.medicalnewstoday.com/articles/321422.

You might want to join this discussion to learn what others have shared:
-- Sudden severe dizziness when standing up: https://connect.mayoclinic.org/discussion/sudden-severe-dizziness-when-standing-up/

Have you considered seeking a second opinion at a teaching hospital or major health facility like Mayo Clinic that use patient centered care?