Can amox-clav 125 mg cause a urinary tract infection or an yeast infection?

Any antibiotic can cause a yeast infection.

"May cause the overgrowth of the yeast, Candida, causing thrush (a yeast infection in the mouth) or vaginal yeast infections."

Source and important information: https://www.drugs.com/tips/amoxicillin-clavulanate-patient-tips

"Oral amoxicillin/clavulanate is a community workhorse antibiotic, routinely prescribed for respiratory tract infections, skin infections as well as urinary tract infections (UTIs)."

Source: National Library of Medicine

Do inform your Dr. about the yeast infection.