You have good reason to be concerned: Sexually transmitted diseases are on the rise, according to the Centers for Disease Control and Prevention, with 19 million new cases occurring each year. Unfortunately, infections aren’t detectable in your body immediately, so you’ll have to wait an anxious week or so before you can see your doctor to get screened for chlamydia and gonorrhea, says New York City gynecologist Carol Livoti, M.D.—and then another three to seven days for the results. “A course of antibiotics will nix these bacterial infections,” says Livoti. “But if left untreated, they can cause long-term damage and harm your fertility.” You should also schedule a follow-up appointment in three months to get a blood test for hepatitis, syphilis, and HIV. “These take longer to show up in your system,” she explains. There is one thing to address right away, however: Unless you’re on the Pill or using an IUD, you should take the morning-after pill (available over the counter) ASAP to ...