Hello and thankyou for approaching DoctorSpring with your query.

I have gone through your case and understand your concern.

I understand that you have a history of blood disorder and cervical cancer. The first possibility for your shortness of breath, lack of energy and fainting is anemia or low Haemoglobin. It could be related to your previous conditions. I would like to know what kind of blood disorder you are diagnosed with.

Another possibility is that your symptoms could be precipitated as a result of your thyroid. Patients with hyperactive thyroid do present, with fatigue, rapid heart rate, tremor, sweating, nervousness. In some cases patients have shortness of breath and chest pain.

And it could be just a vasovagal syncope attack. And finally if the fainting recurs a neurological course has to be ruled out.

Considering your symptoms of tiredness I would recommend a baseline testing which should include -

1) ECG 2) Chest X Ray 3) Thyroid Function Tests 4) Complete Blood Count.

I hope this has helped. Feel free to ask followups. Do visit ER if the symptoms presists.
Thankyou