Please reassurance is needed

Here is my story. On April 7 i had sex. He only was in me for no more than a minute He had a condom on the whole time. And he never ejaculated in me because it was a short time. I was believed to be near or on ovulation. I panicked and took plan b, 7 hours after. I started spotting a week before my period. And then the day before my period was supposed to come i had large clots so I assumed it came early. The large clots lasted 3 days and i had spotting the last two. I know some people bleed in pregnancy which makes me nervous. Could i still be pregnant based on my situation.? I tested with first response today 4 weeks and 4days after sex and it was negative. Should i still worry? Or is there 100% no way I’m pregnant