You might not loose it I'm onto my 4th pregnancy and I've never lost mine ( would of lost it during active labour from what I've read ) So if you don't see it or notice it i wouldn't worry a lot of people loose bits and it grows back so doesn't mean anything
I lost mine at 21 weeks! Common pattern for me was that each morning when I first got up, first wipe there was what looked like alot of snot on the tissue! There isn't always blood which is a common misconception, it also doesnt feel like anything from my personal experience. But it can fall out and grow back so if you do think it's come out, it doesn't necessarily mean baby is coming sooner than expected haha. However it's good to get checked, sometimes it doesn't grow back and then you are prone to infection
For me I thought I might have lost parts of it a few times but wasn't 100% (I think it can come out a bit at a time?) but when it properly came out it was very obvious- for me at least 💕for me it was pretty soon before labour started (maybe the same day if I remember correctly) but everyone's different and my experience very well be complete opposite as I was induced twice to speed things along xx