Can someone help me?

my bf and I had sex on my ovu without knowing but wore protection, the second day as well just once without, but he never came in me. On the 3rd day, we had a quickie, and I started bleeding. I then bleed for 2-3 days like spotting. What does this mean? I took a pregnancy test after 9 days, and they came out negative. Now I am 4 now 5 days late. What does this mean? I'm 18.

When bleed or spotted, was that my period?