What Causes Swelling In Vulva With White Discharge?

Hello. My vulva is now currently swollen. It has been swollen before, and my right vaginal lip was still swollen but despite this, my partner and I wanted to try intercourse again today. I've also had white, cottage cheese like discharge. Right now it hurts and it is incredibly hard for me to walk. I am very scared. I am also three days late on my period, but I took a pregnancy test and it came out negative. Please help. I am pretty sure I have a yeast infection and was planning on purchasing one of those three day treatments at my local pharmacy. Thankyou for you time. -Carmen