Help? Advice? Idk

Hello, I’m 15 turning 16 soon and I’ve been experiencing severe heart pain for a while now, I’ve been to the hospital for it and they found nothing, got blood test and they came back fine and I’ve almost passed out just from stairs, I have a heart monitor rn for about a month now to watch my symptoms I’ve been experiencing. I’m a health occupational student going to get my CNA’s license so I’ve had medical anxiety for a bit now and it’s only getting worse from this. Whenever I have my hands down and bring them up my hands are red from blood pooling and I have issues standing up so I’m suspecting POTS but I don’t want to self diagnose. I have a stress test next month but please help me. The chest pains are so bad I just want to cry