I'm really sorry to hear that, hun.
Allow me to tell you a story, it's a true one.
7 years ago, at age 16, my older sister found out she was pregnant. Like you, she didn't know how it happened, for she was a virgin, but something happened at a party she went to, just like you.
She found it so fucking difficult to tell the family and her friends. She didn't have a boyfriend at the time, which confused her more. She told me she remembers thinking "I don't have a boyfriend. I lost my virginity to some random boy and now I'm pregnant. God, I'm such a slut."
When she told the family, she basically decided she'd tell the parents first, before telling her siblings (me, my other sisters, and my brother). She told our mother first, because she became a mother around that age too. She basically said it straight to the point, "Mom, I'm pregnant." Same thing with our dad (except she said dad, not mom). They supported her from the start, and while they were a little shocked, and a tiny bit disappointed at first, they supported her when she decided to keep the baby.
7 years on, at age 23, she's glad she kept the baby. She is the mother of a beautiful little girl, and I'm proud to call her my sister, and whenever I'm out with them and people I know ask who they are, I'm proud to say, "That's my sister and niece."
The point of me telling you this is to tell you that while your parents might not be too happy about it at first, they'll support you in every decision you make. If not, fuck them. It's your body, you decide what to do with it.
You have my e-mail. If you need to rant or cry or whatever, hit me up! I may not be able to give good advice, but I'll listen.
xox Maria