Hello!
Welcome and thank you for asking on HCM!
I understand your concern, and would explain that your symptoms may be related to a metabolic disorder or a vitamin or electrolytes deficiency ( based on your medical history for 
celiac disease). 
I recommend consulting with your GP for a careful physical examination, a resting ECG, a chest x ray and some blood lab tests:
- 
complete blood count (for chronic anemia)
- kidney and liver function tests
- ferritin and hemosiderine plasma levels
- blood electrolytes 
- vitamine B12 plasma levels
- thyroid hormone levels (an immunological disorder could lead to 
thyroid dysfunction and celiac disease as well). 
A head up tilt test may be needed to exclude a possible 
orthostatic hypotension. 
Meanwhile I would advise you to avoid straining physical activity and take plenty of fluids (water, juices), to avoid 
dehydration. 
Hope to have been of help!
Best regards, 
Dr. Iliri