Pregnancy symptoms?

My SO & I aren’t “trying” but we’re also not preventing. About 2 weeks ago, we had unprotected sex continuously a few days after my period ended. Then, this Sunday we had unprotected sex again but this time during my fertile window. I took a plan b today. These past few days however, I’ve been feeling nauseous every time after I eat. I’m starting to wonder if it could be a stomach bug or pregnancy symptoms?

Any insight would be helpful ❤️. Also, if I was pregnant, the pill wouldn’t hurt the baby right? Thank you.

Also, I did take a home pregnancy test a couple days ago & it was negative