I just got over a yeast infection. last night was the first time i had sex since the infection and i have yellow, smelly discharge now. what is it?

BV? Trich? STD?: Was yeast infection professionally diagnosed? Or just assumed based on symptoms and self-treated? If not already done, you need testing for STDs (gonorrhea, chlamydia, trichomonas), and for bacterial vaginosis. Colored discharge usually means infection, and strong odor is associated with BV and trich. See a doctor ASAP for exam and (re)testing. Also ask partner if any discharge or other symptoms.