NuvaRing & Heavy Bleeding?

So my ccycle start last Tuesday after I took my ring out on Sunday. I usually leave it out for 4 days (instead of 7) then out in a new ring. I have PCOS and was instructed to only leave it out for 4 days. My cycle started slowing up two days ago but then last night and this morning it was heavy 😳. I've never had this happen near the end of my period before, and I've been on NuvaRing almost 3 years. Has anyone else experienced this?