Yeast Infection

My girlfriend gotten a yeast infection almost a week ago. She came over and we fooled around ( we are both girls) but I didn't go down on her because of it but a couple days later I got one. It's odd. At the same time i dont think its one but i am itchy. Thats it no discharge or anything. Can anyone explain to me how we both got one but at different timing. Thank you 😊