Late period 16 days

I noticed brown/ pink discharge a week after ovulating & I’m now 16 days late but still no positive pregnancy test.

I don’t believe myself to be stressed, I haven’t had sudden weight loss, overweight I don’t exercise or take the pill & I’ve been tested for pcos as my mum had these but supposedly negative.

Could I be pregnant but it’s still not showing up yet? Or is it likely it could be something else