Ovulation test

Alexa • I am 25 years old. I have 5 beautiful babies ages 7,6,5,3 & a angle to watch over me! We are expecting baby number 6 in June 2016 if everything goes as planned!!!
I am new to these and have taken 4!!! I see the positive one but now I barely get a line!! I know when its bright blue that's a positive!!! What do this mean can some explain please why the line disappeared when I took one this morning.