Can you feel the coil threads?
A lost coil (I don't mean inside your body, I mean one that has fallen out without you noticing) can lead to a return of heavy bleeding.
Other possibilities are - your body just doesn't like or is taking time to get used to a foreign body in the uterus. This may settle with time.
Infection needs to be excluded, this can also cause pain and bleeding with an IUS.
Migration of the coil can also occur but is rare.
If you have any tranexamic acid you could take that whilst waiting.
