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The symptoms that you have could be due to anaemia, weakness, stress of work and possible TIA (transient ischemic attack). When you meet your doctor, discuss about all these possibilities. You will need to do blood work-up for all of these including EEG for brain after any recent such episode (within first 48 hours of the unconscious episode)
Make sure to have a good well balanced diet, sleep for 6-8 hours every day, and drink plenty of water.
Take care.