I had unprotected sex with a new partner. Couple days later had symptoms of a yeast infection but now I'm worried that it may be something else. Help!

Yeast? STD? Herpes? You don't say exactly what symptoms you have. Maybe it's just what it feels like, a yeast infection. (It's not an STD, but symptoms may be triggered by having sex.) Herpes is the main STD cause of vulvar or labial irritation or itching. Gonorrhea or chlamydia less likely but possible. Don't screw around with this: see a doctor or clinic ASAP. Good luck!