Suggest Remedies For Sickness In My Stomach After Having Unsafe Sex

the reason for this is because this past thursday I had sex and when we finished I noticed the condom was half off/dangling. I don't know if he had JUST pulled it down or if it was slipping off by itself during. I'm scared because I can't remember when my last period was exactly and I'm scared that there could be a possibility that I might be pregnant. I'm not on birth control either which contributes to me feeling scared. Since that day, I've been feeling a little sick to my stomach but I think that's just me myself more nervous over nothing.