Low resting heart rate (woke up with it week ago)

Last Thursday, I woke up short of breath and lightheaded, so I checked my heart rate about an hour later, and it was only at 43, and My normal resting heart rate is 78 or so. It’s stayed between 40 and 55 since then. Two days later, I went to the ER where they did a blood test and an xray of my heart. They released me saying I was stable, and that there was no signs of heart damage nor signs of any clots, but to see a physician within 3-5 days. I am unable to see a doctor due to the lack of insurance, so I am wondering if anyone could tell me what this is. I had a traumatic event happen to me 4 days before the first day if the symptoms, and I was in pure “fight or flight” mode with my adrenaline pumping almost nonstop. I seem to have a lack of it, so I brought up secondary adrenal crisis to the ER and it was dismissed. Please help Age:30 Female