Dirty looking discharge at 17+ weeks

Maya

I have noticed recently this dirty yellow and brownish discharge on both my panty liner and sometimes when I wipe. I don't think it's blood but I can't think of what it is. It's more of like a streak or stain. Anyone else have this before? My nurse told me to just monitor for now but I can't help but worry! Especially since it'll be more than 2 weeks till I see our Bean again on the ultrasound 😦