Are you infections Orally or vaginally?
Are you sure that it is yeast by being tested?
Sometimes the coil can just produce lots of vaginal discharge.
Does this itch really bad? Do you notice an odor?
Then I doubt that it is yeast but it may very well be a bacterial vaginitis. This is treated with Flagyl or Metronidazole is the other name.
This can be causing pain after intercourse, however, if the placement of the coil has slipped that too can be causing pain.
So, you will need to see your provider to help you with both issues. They may want to do an US to make sure of the coil placement. They can test you for the bacterial infection as well.