Confused

I was using the advanced digital opk and ran out after getting 4 days of flashing smiley's which has never happened to me. (Normally go from 0-peak) so I ran out las night and store was out of them so I got the older clear blue digital pink ones that aren't advanced it hasn't given me a peak yet! But my Basal tempting says I have ovulated have I missed something ? Can it happen in afternoon and you miss ?