My period is lighter & shorter?

bri • Sun, May 15

I just got done from horrible nausea & vomiting confirmed unrelated to pregnancy for like a week, and right as my illness started, so did my period, but it only lasted only 2-3 days and was lighter than usual. I wasn’t able to eat anything. I also had unprotected sex two almost three weeks ago. Could I be pregnant or was it just lighter because I was super stressed and ill?