yeast infection or pre labor discharge?

I'm 34 weeks and my baby is expected to come early (he's tried coming at 24 and 28 weeks) and the past few days my underwear have been soaked with a watery liquid that has now changed to yellow gooey discharge. Is this a yeast infection? Or normal discharge at this stage? (I'm on antibiotics for a uti, so thought maybe could be yeast) but I don't itch or burn or anything. Thoughts?