Mirena IUD removal

I had my IUD removed 3 days ago and I removed it cause I had black blood come out and spotting and then I felt the string...After I got it out I had a little more heavier bleeding and 5 blood clots came out...I just started taking the Tri tho Sprentic yesterday...My Husband and I had sex yesterday too...My question is What is going on with my body? I have 2 kids already and it took me a year to get pregnant with my daughter after my son and I have been on the IUD for 8 months and didn't spit or have my period. Does anyone know what is going on?