Hello and thank you for using HCM. I carefully read your question and I understand your concern. I will try to explain something and give you my opinion. I thinks this symptoms seemes to be related with a heart rythm issue. You should know that the heart has her own electrical system. The electrical impulse passes through the heart and makes it to contract and function normally. There are some pathology s of electrical system of the heart that might cause arrhythmia and heart electrical pauses. The symptoms of this kind of pathologyes are palpitations,skipping beats fast heart beats, difficulties in breathing deeply when the heart experiences arrhythmia and than other symptoms like feeling tired or losing senses in bradycardias or electrical pauses. To diagnose this rhythm problem it is necessary to do some examinations. So, if I was your treating doctor i will recommend to do an electrocardiogram, a cardiac echo, a fool blood test and the most important one holter rhythm monitoring for 48 h. This examination gives us the chance to monitor your heart rhythm as you feel tired, sleepy or experience heart racing. Only after this my can know what we are dealing with and how to treat it. Hope I was helpful. Wish you good health. Best regards.