Really confused

Ok so I’m really confused,my af last month was a day and a half and now this month I came on a week early (never been early before) I thought it might of been implant bleeding so I did a test and it was a bfn . So I was on for 8 days as well witch I’m only ever on for 4 at the longest x I felt strange when I finished so I started using my ovulation tests and got low (the day after af) high ,high and now peak! So how can my body be ovulatiing 3 days after my so called period? And y was I a whole week early ?