5 days late but not pregnant

My husband and I are planning to start trying soon so I’ve been doing some experimenting with some ovulation tests this cycle hoping to catch my peak and see if I could see my symptoms to look for as I got closer to it. I hit my peak late the 8th into the 9th of May but now I’m five days late and know I’m not pregnant as we aren’t currently having sex due to health things on my end I’m in PT for. Is it possible I’m not actually ovulating when i thought despite getting a positive opk?