You should get tested as soon as possible, and since testing can usually be done on a confidential basis, it is not necessary to go with your parents. To find a clinic in your area, you could call 800-762-2296 or click here. Or you could call a local crisis pregnancy center or hospital, and they can refer you to a clinic for testing.
Regarding your parents: You may think, “What Mom and Dad don’t know can’t hurt them. If I did tell them, my mom would cry for a week, and I would probably be grounded until I'm 40.” As difficult as this may be, put yourself in your parents’ shoes. Imagine you had a child who was sexually active. You would want your child to be able to come to you and be honest about whatever was going on in his or her life.
The sooner you get a real relationship with your folks, the better. Sure, your parents will be upset, but under that hurt are two hearts that want only what is best for you. Some teens shut their parents out of their lives because of pride. If they had listened to their parents in the first place, they would have avoided so many mistakes. Swallow your pride, and do what you would want your own child to do. Even if you refuse to tell them, make sure to get tested. Some STDs can be easily cured but may lead to infertility or even more serious consequences if they are not treated.