Fainted seventh time

Patient: Hi, i am 20 years old (female). yesterday i fainted during class. This was my 7th time in life. i first fainted when i was 8years old (because it was a hot day as far as i remember). yesterday i did not have lunch and before my class(in the evening) i ate a pack of biscuits. whenever i am about to faint i feel nauseous. and yesterday i noticed that my nails turned bluish.i just wanted to know if this is normal?

Doctor: