is it possible I could be pregnant?

I had sex on the very last day of my period on December 29th. It’s now 3 weeks later and my period came on 1 day early this week but I’ve been feeling nauseous everyday this week. I know a missed period would typically be a sign of pregnancy but I’m finding it odd that I’ve been feeling nauseous everyday as well and not feeling like I want to eat like I normally would. I’ve never felt nauseous on my period before. And the timing is just weird. Any thoughts on if there could be a chance of pregnancy here?