Getting really discouraged.

Last month i ovulated on CD16 and 17 i didn’t notice a second line until CD14 and it just kept getting darker. This month it’s not like that. I started testing on CD11 I am now on CD17 and there is nothing. I am getting really discouraged. I never know when to start testing. I also have been having really bad cramps on my left side. I’m worried something is wrong. This would have been our first month trying.