Funny story.. my husband suspected I was preggo before I had any idea. To put his mind at ease, I went and bought a test at CVS. I took the test and barely saw a line. I thought it was negative and threw it out. The next morning, my husband must have pulled the test out of the trash can and texted and said even though the line was faint he could see if and said it may be positive So I left work briefly, ran to the store and bought a digital test. To my surprise, the digital test read pregnant. I really thought I was going to show him the digital and say see another negative test.
We were trying for a while and I just couldn't believe I threw out my first positive test because the line was faint blue. Luckily he second guessed me and made me take a digital the next day! lol
So in conclusion, if you aren't 100% sure go take a digital to confirm.