Pregnant? Do you spot if you're pregnant?

You did the right thing by getting the Plan B so fast. It is effective up to 72 hours after unprotected and can make you feel uncomfortable though many people say it can't (FIRST HAND EXPERIENCE.) The symptoms your describing are the start of a cold and since you aren't on Birth Control yet the brownish substance could pre-period spotting. Not uncommon. I don't think you have anything to worry about. If your period does not come on time, you may want to consider taking a pregnancy test 3 to 4 weeks after the condom incident occurred. I also suggest you wait until after your period to begin your birth control so you stay on the same regularity as you're used to. It's easier on you and your body.