I had the same issue after stopping my birth control. I used the app called my days and it helped tracking my off periods a lot!
Yeh :( we fell pregnant straight away as my periods were always on time and I was spot on with my most fertile days. But since having bubs they been all over shop
Possible, yes. Likely,no. Unless you have extremely off periods it's unlikely that you ovlulate 2 days before your period. It's usually 2 weeks before your period. If you're 6 days late take another test in a couple days. Pregnancy tests are usually pretty accurate though, we were trying and my periods were really off from stopping birth control so it was extremely frustrating