Overthinking?

I recently had unprotected sex with my boyfriend (not during fertile window) but it’s been a week and I’m feeling quite nauseous. I know you don’t get nauseous the first week if i am conceived, so I am kind of confused. I am also bulimic so I not sure whether if it’s purging tendencies or just nausea (since I’m working on trying not to purge for the past couple of days)