Hi. Im 19 Years Old And Today I Started My

Hi. Im 19 years old and today i started my period. It's way lighter than usual and I had spotting for 2 days before it. Im sexually active but i always use condoms. Also i deal with a lot of stress for the past few months. My periods are always regular, only last month it was one day late. Could i be pregnant or is it because of stress? I did a test before my last period and it was negative. I cant do it now because im having a period at the moment. Please answer.