Is this really a lifestyle issue?

Female 27 130 lbs and 5 feet

I have a cardiology appointment lined up for a stress echo and holter monitor. I already had blood work, an EKG and a chest Xray. My blood work showed mild subclinical hypothyroidism, and they weren't concerned about this.

My symptoms are:

• chest pain
• being out of breath easily
• high heart rate at rest (get Fitbit notifications every single day)
• high heart rate when moving (190 on a casual stroll)
• purple lips daily when I'm hot not cold
• high blood pressure
• hypoglycemia frequently
• fatigue (I sleep 13 hours a day with no relief)

My bf insists the Drs just going to tell me to eat more, hydrate more and exercise. It's true that the most exercise I do is 10-30k steps, and I mostly drink iced coffees and eat sporadically not 3 meals per day. But at my age and overall health (which is really good, weight could be slightly better) does that make sense?

Just wondering if I'm doing the right thing doing all the tests? Or if I could treat it like he thinks?