Can pregnancy tests be faulty?

Hey y'all, so I took a pregnancy test just to ease my paranoia of thinking I'm pregnant (although I know there is no way because he didn't cum, and he didn't even put it inside of me) within the 10 minute window, it said it was negative. My paranoia was at ease, I was screaming to the Lord and all. Then before I threw it in the trash hours later, I saw a faint line. Ya girl is paranoid once again. I looked up what it could b, and a lot of people talk about an evap line. I took one of the tests with the blue dye. Any advice?