I have been diagnosed with POTS or Orthostatic Hypotension, because I feel lightheaded and lose my vision (black out) a lot when I stand. I go through periods of a few days when it happens much more. I also feel very lightheaded, my heart pounds, it is harder to breathe, and I feel like I m going to pass out while in the shower, and my heart also pounds and races when I wake up from naps. Are these symptoms of Orthostatic Hypotension/POTS, or should I get my blood taken/see a doctor?

Summarized question: Does orthostatic hypotension or POTS cause these symptoms?