4 days late, test negative

Ceri 🍋

Hi all...looking for some support. My period is now 4 days overdue which NEVER happens. I’m always regular to the day. We’ve been TTC since January. I took a test yesterday and it was negative. The tests say they should pick up even before your period is due, so I’m confused. This would normally be the last day of my period, but nothing...could I be pregnant? Has anyone else taken a while to get a positive and had false negatives?

Thanks