I need help

I think i might be pregnant. Im only 18. I have no idea how to work this app. Im in college. My boyfriend is amazing. We have no jobs. I would of just finished my period today. Not even cramps. No discharge of any kind, no spots. Nothing. I took tests but they are all negative. However the line is so faint you can barely tell its there. Any thoughts? No i havent told anyone but my boyfriend.