Nauseous

So today is my 4th day of my period..its really liglight..usually its heavy the first days but this time around it was some what light..rightnow its reallyyyy lighttt almost nothing and my pd lasts like 5 to 6 days...so right now i was laying down and out of nowhereee vot super nauseous..went to the rr and threw up saliva 😷😣 never happened before..i really dont kno whats happening l..any suggestions ?