Clearblue advanced OPK

Mallory

I had an SHG done on CD 11 on 4/26. Two days ago I had 2 flashing smiley faces and today I had a flat out “O”. I had a shorter cycle last month 26 instead of my usual 28 and have been regular since my IUD removal Dec 2017. Could I have missed O? Or could it just be coming later this cycle? I’m so confused and let down. TIA!