Could Digital OPK be wrong?

Stephanie
I am so confused! I have pretty regular 28 day cycles. Clearblue digital OPK showed smiley face on CD8. It changed my period from coming 10/1 to 9/25. Still no AF. Could I have ovulated later than I thought? I got a BFN yesterday which was CD26. Thanks for any and all insight ladies! Baby dust to you all 💕