possible miscarriage infection

i had a miscarriage last week on wednesday. I was 12 weeks, but im not sure if the baby was that old or not. it started as light bleeding early monday then by wednesday it got heavier and i had really bad stomach cramps and a back pains, so i went 2 da emergency room, they took some blood & the nurse told me i was having a miscarriage. after that i went home and bled heavily until thursday when it got light then thursday night i was on the toilet and a big sac came out of me. i think it was the sac with the baby in it but im not really sure. since that day my bleeding has been really light like its ready to stop but i am still having back pains, and my stomach is starting to hurt again. last night i started to smell something really bad, like a dead animal then i realized it was me and before i got ready to take my bath i noticed the smell was coming from the blood on my pad and i was wondering could i possibly have an infection