So early already?

Hi!
I'll put it in the first trimester section. Although I don't even know if I'm pregnant myself.
There are probably already hundreds of topics with complaints.
I already have a daughter who's almost 4. I've also been off the pill for half a year. I have a new boyfriend. We've known each other for 14 years but recently it became a serious relationship. But that doesn't matter further. If it sticks. It's welcome with open arms! We practice withdrawal. And we are both aware that this absolutely does not work 100%.
I know exactly when my ovulation is. And keep track of everything.
We had sex two days before my fertile day. Although not inside me. But we weren't careful. The night I was supposed to ovulate, I was so nauseous that I had to throw up.
This was 5 days ago. I'm still nauseous. And since today also extremely dizzy/spinning.
Could this be related to a possible conception? I have a fixed cycle of 25 days. Maybe my ovulation was earlier after all?
Thanks in advance for your answers! :-)