missed birth control, never had sex, and spotting for 2 weeks now

I'm 18 and I've had kind of a simliar problem. I've always had regular periods but about maybe almost 4 months ago I started birth control because I'm on an acne medicine that you cannot get pregnant on. I have not had sex any time while I've been taking the pill, due to the severe birth defects involved. I got my last period on time, however two days after it ended, I forgot to take my pill for four days in a row while I was on vacation. I took it again once I got home that Friday. On Saturday, I started having something light pink bleeding. I continued to take the pill everyday, but there has been spotting for the last two weeks. Some of it is blood but it seems like there is also a liquid as well? My period should start in a few days. Can anyone help? There are so many mixed answers on the Internet, its scary. Please help :(