Is it normal to get yeast infections after sex?

On Friday night I had protected sex with someone I’ve been seeing. Saturday I was asymptomatic and Sunday my discharge was thick and white and accompanied by discomfort surrounding my vulva/vagina. Typical yeast infection symptoms. I’m just wondering what could have caused it? I don’t have sex very often at all (this is my second partner ever), so maybe my immune system just freaked out? Any similar experiences when you first became sexually active?