Worried

Period is 4 days late.

I had PROTECTED sex the first week of October (only once) and it was on the last day of my fertile week.

Should I be worried.

I'm pretty naive because I grew up in a super strict religious home where instead of teaching you about sex and how to be safe all we were taught was it's a sin before marriage and it's purpose is for children not pleasure. You were literally just told sex is a sin and you were to avoid it until your husband said so