YEAST INFECTION

hey ladies so i hope you can help so i went to a exam and they told me they found an infection on my cervix (yeast infection) and i asked what might cause it... sex, washing undies with regular laundry, or body wash that has fragrance in it. I recently has sex with my boyfriend of 2 years with out a condom and as we were having sex. i began to drip very creamy white discharge. two days later same discharge but with a smell and a very small amount of itchiness, now im kind concerned if it can be a simple yeast infection or sound i be concerned he maybe have sexual intercourse with some else. please tell me im over thinking this... also these symptoms happened all within the few 24 hours of have sex with my bf

thank you in advance !