broken condom... please help!!!

My boyfriend and I had sex about 4.5 weeks ago on Jan 13th, 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. Today is feb 11th and my period is now 5 days late, and I know that there's not much I can do other than take a pregnancy test, but the idea of getting a positive read makes me nauseous. I was 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.