On 30th March, A guy rubbed his penis on my vagina, it lasted hardly for 10 seconds. He didn't ejaculate, and there was no penetration. But I was anxious about pre-cum, so on 31st March (within 48 hours), I took a postpone 72. My periods were due on 8th April. On 7th April, I started bleeding, slightly lighter than my regular periods, which continued till 11th morning. On 13th April, I took a urine pregnancy test, it was negative. I took another on 22nd April, also negative. Today is 26th, my nipples feel a little sore. What are the chances of pregnancy?