Weird question - IUD period related

Hi ladies,

So I just got my iud implanted earlier this month around March 6. I spotted for around 5 days after implantation then got my period pretty normal for 5-7 days (a little longer than usual). As it came to the end, I had sex 3 days in a row and I noticed light minimal bleeding afterwards which would normally happen after I had sex on my period so I didn’t think too much of it. I got my allergies this week and have been taking Zyrtec and Mucinex. After taking Mucinex, I noticed a lot of bleeding! No pain though associated with cramps or anything just bleeding. I looked up online since Mucinex literally thins mucus, it may also thin the cervical mucus which my IUD is trying to thicken. It’s kind of annoying because I thought I was done with my period and I’m on vacation next week. I’m seeing my primary care tomorrow and going to run it past her. Just curious if anyone else has experienced this...?