Dealing with Orthostatic Intolerance and POTS Diagnosis

I have been diagnosed with orthostatic intolerance and my doctor said i’m on the “edge” of being diagnosed with POTS. i go to physical therapy for my hEDS and when i was there today, and whenever i’ve been going for the past few months, my heart races really bad, my chest hurts, i get dizzy, and i feel like i’m going to throw up. i tried calling my cardiologist to schedule an appointment because i feel like crap and the earliest thing they have is in february. i’m eating my salt, wearing compression clothes, drinking water and gatorade. i don’t know what else to do. i’m tired of chest pain and nausea. i’m used to the dizziness and tolerating it. any advise?