After birth, it is expected to have vaginal bleeding for a while, whether your baby was born vaginally or by caesarean. This blood is called lochia and is part of your uterus's recovery process.
During pregnancy, the placenta was attached to the wall of your uterus through an area with many blood vessels. After the placenta comes out, there is an area in the uterus that needs to heal. This is mainly where the blood from the first few days comes from, along with mucus and tissue from the lining of your uterus.