Hi There, I Have Probably A Simple Question About Feminine

Hi there, I have probably a simple question about feminine problems. I have the past three days noticed a clear odorless vaginal discharge ( sorry to jump right into discharges right away) . It is becoming yellow tinged. I am 57, post menopausal, nothing different has happened to explain this. I am sexually active, already asked the BF about any STD's which he vehemently denies. I have to change the pantiliners VERY frequently, and it's not going away... Do I see a doctor? Treat with probiotics? Any suggestions? Thank you very much