broken condom... any idea of my chances of pregnancy?

Julia
My boyfriend and I had sex about 3 weeks ago, the day after my period ended (which also happens to be the day before your fertile window starts). We used a condom, but I had a weird feeling as he was about to cum that the condom might have broken so I told him to pull out just in case, but I didn't tell him in time. He came on the way out, and it turned out that the condom WAS broken. Most of the semen went around my vulva, but some of it still went inside my vagina. I went to pee immediately and rinsed my vulva with water to wash away all of the sperm that I could. Then we immediately drove to CVS and I took Plan B. I'm supposed to get my period in 6 days, and I know that there's not much I can do now besides wait and see whether I get my period, and take a pregnancy test if it's late. But I was just curious if any of you have gotten pregnant this way? Or maybe know any early signs of pregnancy or (I hate to say this) natural ways to induce a miscarriage? I'm in college and I'm not in a place financially or emotionally to have a baby.