3 days late, brown spotting, negative pregnancy tests

I have super regular 27 day cycles.

We have been trying to conceive baby #3 for 3

Months. I have always got pregnant first month of trying for my 2 children and 1 miscarriage.

This cycle I started testing around 10dpo and got BFN.

I then started getting brown/pink spotting like I always do the 2 days before my period. But this cycle, no period has come.

I am now 3 days late for my period, no period cramps or feeling that it’s going to start. Brown spotting on wiping, but still negative pregnancy tests.

I am so confused!

Does anyone have any thoughts?? Xx