Late period, help!!

I am 20 years old. My cycle is typically between 25-27 days, bleeding for 5 days. My period is a week late, which has never happened. It’s either always right on time or early. My partner and I had unprotected sex (I’m sorry, I know I shouldn’t have 😭) two days after I stopped bleeding, nowhere near ovulation, and I took plan B immediately after. I don’t have my usual premenstrual symptoms. I took a pregnancy test yesterday and it said negative. I’m just so anxious and so so scared. I can’t do anything. Am I pregnant? I’m normally always so careful, I feel so stupid.