Late ovulation on Clomid?!

I ovulate on my own cd18-19. I took Clomid for the first time (50mg) on cd3-7 and was told it failed on cd17. Today is CD21 and another doctor told me I either just ovulated or will soon, my only mature follicle is 19mm. I'm really down about it but slightly hopeful, has anyone ovulated really late, especially if they ovulate on their own?

This was my opk today, I stopped doing BBT because it stresses me out.