confused? when will I ovulate?

I had cervical mucous and now it has dried up but I have been doing ovulation tests and have all been negative. I only had one day of egg white last week but did not test then as it day 16 and last month I ovulated around day 21 which was yesterday. Have a ovulated already? Or shall I keep tearing? My periods are really irregular ranging from 20 days to one being 56 days. Confused