Advice please ladies! Opk negative... "Fertile week" though. Help!

Ok so this is my first month of doing opk, as been off bc for 9 months. I'm testing on average at about 5/6pm as I'm at work all day. Been testing since Tuesday, but all been negative... No line what so ever. Apparently tomorrow is my peek day, according o apps, so surely I should have had possible by now??
My periods have been more regular last 3 months...29/30 days. So could it just be that actually I'm going to ovulate late. I know I just need to keep testing. But need reassurance and as I e. This happened to anyone else? 
Thankyou xxx