Pregnant?

This is my first time posting and I’m just so conflicted. My period is currently 13 days late. I’ve been on the pill since I was 16 and I only just 2 months ago changed the dosage. My period has always been on time because of the BC and even my first month of the new one was on time. My second period never came. I only had 2 separate times of a small spot in my underwear one one day and then once more the next day and that was after my bf and I had sex during the week I was suppose to have my period. Other than that I’ve had nothing. Very very light pains here and there. Only puked twice. Very irritable. I took a test a few days ago and it’s negative. Just wanted to see what you guys thought.