You were on your period which is not in the fertile window. Ovulation is about cycle day 14 and sperm lasts inside no more than 5 days. Once ovulation is a couple of days past, the egg is no longer viable. Download a period tracker which will help you understand this better.
Your guy is pressuring you to have sex, which does not mean he loves you, just that he’s a typical young male for whom sex is everything. Tell him you are not ready to take risks, and if sex is so important to him he needs to find someone else.