10 days of opks not getting darker :(

Hi all. I'm on CD 19. This is my first clomid cycle (days 3 to 7, 50 mg) and I haven't had any progression at all in my opks. CD 15 looks slightly darker but it really wasn't when I tested. I'm getting stressed out that I'm not going to ovulate this cycle (which is why I was put on clomid). Anyone have any insight? Is there still hope for o this late? I'm supposed to do blood work on day 22...bbt is all over the place, everywhere but up! :(