K.P.
Don't ever let your Dr go without telling him everything you want to tell him. A lot of times Drs want to rush you in and out, but they're getting paid a LOT of money, and you are going to him to make sure you and your baby have a good and healthy pregnancy. Sometimes yellow can mean an infection, but sometimes it can be totally normal. I would call your Dr or Nurse Practitioner and ask them. If he feels he needs to see you, he'll tell you to make an appointment, but maybe he can tell you over the phone if there's nothing to worry about or prescribe something for you.