Get yourself tested. It could be a UTI or a yeast infection or both but don't rule out an STD.
You can't "tell" if someone is infected by looking at them. Many STD's remain dormant or hidden. Every time you have sex with an individual you are having sex with EVERYONE that they ever had sex with.
Unless your gyn/ob tested for it, no. She wouldn't know.
Respect yourself and use protection.