uhhh...wtf gives ovulation?! please help!

Ashley • Pregnant with child #4 after 16 months of unexplained infertility. Just trying to look towards the future. 💋💍🥀🌮🍕🍻🍾 I love my 3 children, MTV's The Challenge & Greys Anatomy!s
Ok so I THOUGHT I had a positive test on cd 14. It was blatantly positive. Took one cd 15 and it was significantly lighter. Took another one today (cd 16) and it's dark again!? Or at least to my eyes it is? Omg what gives???