Help!

So let me start off by saying that we are not trying to get pregnant, but if it happens then we are adults and we know what caused it. I’m 24, and he’s 29. I stopped the pill in November and my cycles were basically back to normal instantly. I ovulate around day 18 or so. I’m on cycle day 15 today. We had unprotected sex last night, and he didn’t pull out. I know sperm can live in fertile CM for a max of about 5 days. It was creamy/watery, more watery though, yesterday and my cervix was high, medium firmness, and open. Today it is high, soft, and open. My temp did go up today, and cm is watery. opk was negative this morning though. I know FMU isn’t best for opk, but that’s how I’ve been having to do it. I may need to start testing at work to prevent that.

SO, I said alllll of that to ask how common it is to ovulate early, or have a high, soft, and open cervix days before ovulation. Any tips or advice are welcome.