Opinions about pregnancy test and birth control pill

So I'm on the pill currently, takes it every day at the same time. No missed pill. My boyfriend and I had sex on the 15th of February and I had him pull out because the week leading up to it, I had diarrhea twice so in the case, the pill hormones didn't have time to work its magic. I also took an ovulating test on the 14th of February and and the 15th and 16th and it says im not ovulating. I know the pill works so it makes you not ovulate but I just want to be sure. Now I took the pregnancy test on the 16th, I know you're supposed to wait awhile but I got impatient. I believe 99% that's negative but there's that very faint second blue line. What do you guys think? Should I take another one next week to be extra safe?