Still no positive opk on cd 23!

Caitlyn
Okay so I'm getting really discouraged! It's now cd 23 and I still haven't gotten a positive on any of my opk's. I've been testing since cd 8! I have only tested once a day and it's my first real cycle off bc so I'm not sure how long I should expect it to be. What do you think is going on? Any insight would help.  Help please! 
Thanks in advance.