Copper iud partially expelled?

I have a copper IUD for 2 1/2 years and last month my period was nothing short of me bleeding to death I even went to the E.R. I was told it is just a large clot and it will pass. I ended up using a large box a heavy flow pads in 24 hours not to mention all the other pads because it lasted 10 days. Two days later I passed the clot or clots should i say. I have experienced a miscarriage before but this was like 5 of them at one time not to get to graphic but handful's . My sister is a RN & she came to look at what i passed and was terribly worried for me. I called my ob-gyn and they sched. a appointment a month away. So that was last month its is 4 days past my regular sched. period and nothing. I went to check my string for the IUD and it is much longer than before I used to only feel the tip of the string but today I could feel the whole string! anyone ever had this happen to them please let me know I'm not alone. I have 4 children and not planning on anymore so I'm a bit scared. My OB-GYN appointment is tomorrow.