A lil over a week ago, i had unprotected sex & then took plan b pill. i think starting yesterday i've been experiencing vaginal itching?? also i'm taking medicine that the doctor said i may get a yeast infection, i'm thinking it's that but i'm not sure.

Yeast is possible: Genital itching is the most common symptom of vaginal yeast, and your question suggests you're probably taking an antibiotic which can trigger yeast infections. There are several over-the-counter yeast medications you could try; look for a product with active ingredient ending in "azole". But first check with the doctor who prescribed the antibiotic; she may want to see you in person. Good luck!