Nauseous or paranoid?

Rachel
My boyfriend and I had sex at the weekend and I was ovulating according to glow and I've just come off the mini pill. We used a condom when he came (as we're not TTC) but didn't before that and he seemed concerned that some went inside me before then.
I know it's too early for morning sickness if I was pregnant but I feel so nauseous and I'm not sure why
Do you think it's just psychological because he was concerned at the time that's making me nauseous? 
I havnt actually been sick but I feel like I will be. 
I just need some friendly advice to put my mind at ease.