Well if you were trying then congratulations, likes its been said already you're going to need to get in to a doctor asap to confirm the pregnancy, you'll need to get on prenatal vitamins as well. You should start education yourself about pregnancy by reading up and researching some sites, I found this one to be quite helpful when I was pregnant with my son:
http://www.planningfamily.com
You're going to have alot of thinking to do, being pregnant isn't something that's easily swept under the rug, your life just took a drastic change and you're going to have to figure out how to juggle everything if you want to make things work. Best of luck!