Hi Lala, I’m so sorry to hear about your symptoms! To determine if you may have POTS, a tilt table test (or even a “poor man’s tilt table test”) will generally reveal it. If it is POTS, locating the underlying medical cause is essential. I’ve seen abnormal intracranial pressure, vagus nerve problems, vascular anomalies, endocrine problems, disorders of the immune system, and abnormal inflammation as fairly common contributors to this condition (among other causes). If you are not able to get to POTS Care, with your dry eyes, dry mouth, and cognition issues, I wonder if you could get some help from a supplement discussed in the studies we released here: http”www.ChronicDiseaseDigest.org Although this discusses its role in Chronic Fatigue Syndrome, it sounds like it may also pertain to you! Gentle hugs…