Spells Of Vomiting, Blackout And Fainting, Diagnosed As Vagus Nerve Problem. Have Delay In Periods, Had Unprotected Sex. Could Fainting Also Be A Sign Of Pregnancy?

I m a nineteen year old female, and I had a fainting spell a few weeks ago. I blacked out and vomited, and was rushed to the emergency room. All tests came back fine, so they chalked it off to a vagus nerve problem. What concerns me is that my period is now four days late, and I had unprotected sex multiple times before my fainting spell. I have been on an oral birth control pill for over a year, but could the fainting and the late period be a sign of early pregnancy? Please help.