Ovulation test line

Charlotte
Hi everyone :-) just a question about ovulation tests. This is my first month using them. Does the line get darker the closer to ovulation. I was testing last week and I could see a second line but not as dark as the main line. I then missed a few days testing... I then have done some test this week and there is no second line. Could that mean I have ovulated already? My cycles are quiet long around 35-40 days :-( hopefully someone can help me x