greenish discharge and itchyness

M
So I've noticed ever since I had my first yeast infection back in December, while I'm ovulating, I get greenish dircharge and the opening of my vagina is a bit itchy. Not too bad to the point I can't do anything, but the feeling is there. I have very good hygiene, I change my liners very often. That was my only yeast infection, it hasn't happened again. And I'm not scratching, but it worries me still. Also, I have an IUD (mirena), but I'm not sure this has anything to do with. I have my 6 week check up next Monday. I've been tested for STD's and I'm all clear. I sat in front of a mirror to see my vagina and it's not even covered in white or green discharge. It looks normal. I don't have a burning sensation while I pee and it doesn't smell either. It just smells like a normal vagina. My inner labia also feels a bit sensitive. 
I read the IUD can give you infections but I'm not sure.