What Causes Ammonia Smelling Discharge?

Hi, I was wondering if I should be concerned about ammonia smelling discharge? I am currently on my period and using tampons. I just went to the bathroom and my panties were wet and it smelled like ammonia. I used to get a lot of UTI's and have not had any symptoms of a UTI. I am 27 years old and have an IUD in which I had a very sharp pain in that area yesterday when I bent over to grab something...but it seems to be fine now.