Lost mucous plug or yeast infection? (TMI)?

Okay, Monday I started losing my mucous plug, or so I thought. Tues I had pretty steady contractions for a few hours then they stopped. Wed. morning I lost more plug in the shower. I went to the dr to get checked since I had the contractions Tues. She said I have a yeast infection. I have never had one but never thought that I did. I had no itching or burning or foul smell or disharge other than what I thought was my plug. I am taking the inserts but I still have a little stuff coming out that I think is the rest of my plug. The mucous that came out looked like snot. Do yeast infections cause twinges of pain in my upper crotch or do you think maybe I am dilating. BTW, I was already dilated 1cm. Any experience with this. I have been very lucky not to have ever had one of these unfortunate lady issues before but had I not had these contractions Tues. I never would've thought I had any sort of infection. And yes, the dr. did do a swab and looked under a microscope to determine my infection. I trust my dr. just a little confused. Thanks!