I feel like an old gross witch. Why are my fingernails suddenly yellow?

HELP!!! I took my nail polish off yesterday and my fingernails are tinted yellow! I have been so embarrassed since. I don’t get what could have caused this. I don’t paint my fingernails all that often. They had been painted for the past month or so multiple times but that is fairly uncommon for me. About 2 weeks ago I took off pink nail polish and they were not yellow, then I put on green and now they’re yellow! I feel foul. My diet has not changed…so….I feel that if I wasn’t deprived of a certain vitamin before, I’m not now either. Anyone have any ideas? Or how can I get them back to a normal color? Ick.