I had intercourse on the 11th, 13th, and the 18th a few times on each day. My expected period was suppose to be on the 18th but I didn't come on. I've never missed a period before. Onthe 21st I bled lightly and noticed a lot of brown discharge. Onthe 22nd I noticed more brown discharge, with a large amount of blood flow. After the blood flow a clot a little bigger than a nickel came out...I thought this was an early miscarriage, but am not sure that could happen that soon. Please help!