Odd discharge?

For the past few months I've had a clear to whitish l discharge. It is at times the consistency of phlegm. Gross I know, but that is the best way to describe it, except it's clear/white. I had my annual pap last month and my doctor checked me for infections/std's and it came back as fine. She said the increased discharge was most likely caused by my birth control. But, I've been on Yasmin for 5 years now and have never had this before, so I'm not sure if I believe that. Has anyone else had a discharge like this?