Confused

My husband and I are not trying to get pregnant. However we do have sex without condoms from here an there. This time we had sex the day my period ended and he ejaculated in me. I'm confused because this is the 2nd time it has happend but this time I keep feeling nauseous when I eat and have no appetite. I also noticed my stomach kept twitching last week like it had a spasm . Does this mean I'm pregnant or just hormones ?