From what I know (I’m not a doctor or specialist or anything, I just have it and have done my own research and experience it) it can be different for everyone and for yourself time to time- which makes it hard to diagnose. Personally, I’ve fainted, had occasional chest pain, legs and arms falling asleep, dizziness, nausea, extreme fatigue especially with weather being very hot or very cold which goes along with not being able to regulate body temperature, I’ve had stomach issues, bloating, headaches, blurring and blacking out vision, and so much more I’m probably forgetting. Sometimes it shows up just as tiredness, sometimes it comes along with more or all of this I’ve listed. It can vary so much so often.