3 day period.

For some reason this month I only had a 3 day period. I started on the 1st and it ended on the 3rd. The next 2 ( 5th & 6th) days there was nothing. Then on the 7th i had some old bloody discharge. According to the app I won't ovulate well till yeaterday. Is that right or would I have ovulated sooner the yesterday? Anything helps thanks.