Positive Stories?

Does anyone have a success story where they were able to do regular sports or activities while managing their symptoms? And what advice you have? I was diagnosed Monday and explains what I have been feeling for the past 2 years. It came out of no where. I use to surf and weight lift, and spend all day at the beach (especially on hot days). Now I can’t go to the beach without feeling like I need to get sick or faint after an hour(if it’s a heat wave forget about it I will feel sick on the drive there). I feel so tired after a week of school and work to even make it to the gym. I don’t know if lying down makes it worse, standing up, or sitting straight. The cardiologist was very dismissive and won’t consider meds until November. Staying active helped a lot of the mental health issues I go through so this is super discouraging. Also what causes this? I am so confused again he was quite dismissive. I just want to see if there is a light at the end of the tunnel, and for anyone else who would like a some good news.