77 days late copper iud

Hello,

I have had a copper iud for the last 3 years and just recently I have missed my period the last time was 2 1/2 months ago. I got very light bleeding for a little and now I have mild bleeding discharge but not enough for a tampon at all. I’ve taken 5 pregnancy test a week apart each time and two different brands and it was negative. I have not had any weight gain or nausea or anything and I can feel my strings..any ideas?