Yellowish discharge 38 weeks

I’ve had some bouts of very watery discharge the past few mornings that leads me to put on a pantyliner. But then the watery discharge goes away and it’s more of a sticky yellowish as the day goes on. The color is maybe more noticeable because I have the pantyliner on, and it honestly comes and goes throughout the afternoon. It’s odorless and I’ve been tested for infections in the past few weeks so I don’t think it’s that. What could it be? Mucus plug slowly coming out? Just normal pregnancy discharge?