Ttc missed period

Hi ladies. I posted a few weeks ago about ovulation tests.

A week before I was due on my period I had light spotting for 3 days and then it stopped.

I am now 3weeks late and pregnancy tests are showing negative. Could I still be pregnant and getting negative tests?

I've also been having backache, feeling tired, hungry etc.

I've never been late like this before. When I had my little girl I got a positive a week after missed period.

Any advice would be appreciated thank you xx