Never ending period post IUD

I got my IUD (Mirena) put in about 8-10 weeks after having my first baby. Around the same time my daughter stoped feeding at night and I got my period back (I think; it’s hard to tell Bc I was already spotting from getting the IUD). It was very light but lasted all month. I told my ob at my follow up. She said she hadn’t had this happen before but that everything looked normal so she wasn’t concerned. She said to contact her if it didn’t stop soon. Has anyone else had something like this happen? I’m on day like 40 of my period and I’m so over the stained underwear 🙄