What Are The Chances Of Pregnancy Post Unprotected Sex Despite Having Nordette Pills?

hi! I had unprotected (interrupted) intercourse. Interrupted because I am positive I pulled out and decided not to push through. I am just worried about pre-ejaculate so I took 4 pills of nordette within 12 hours. I read I should take another four after 12 hours but I forgot. I was able to take it within 16 hours, I think. Also, the act happened a week after my last ,menstrual period so I think I m safe. I had withdrawal bleeding after I think seven days of taking Nordette. I also remember having blood spots a few days after I thought the withdrawal bleeding stopped. This week is supposed to be the week I am expecting my menstruation. It hasn t come yet and I am experiencing nausea and I feel dizzy with things I smell. I m just nervous. I can t give the exact dates because when this happened, my menstruation just came back after giving birth. I was not even counting yet. I hope you can answer my question. I dont want to take HPT yet. I m really paranoid right now. Thank you in advance