What Causes Fish Smell During Menstruation, Abdominal Cramps And Nausea Day And Night?

I am currently on the paragard and experiencing a irregular period. It started 11/30 night. light pink mucus then persisted to brown discharge bleeding on 11/31 all day. On 11/1 it started brown discharged but by the end of the day it was bright red but still fairly light compared to the extremely heavy bleed through my pants periods since I had the iud inserted. on 11/2 the bleeding got heavier but not a consistent flow. Today it has lighted up with a more consistent flow earlier today but slowing down this evening. I have also noticed that the smell is fishy and I ve never had smelly periods. I am also nauseous every morning and night and at least once midday since 11/30 I have been cramping and passing tiny pieces of tissue