Some women experience early pregnancy bleeding. I personally did, with my first son, but no two women are alike and there could be different reasons why different women bleed during pregnancy.
If you get severe cramping and heavy bleeding, you need to go to the ER.
In the meantime, you can schedule an appointment with your doctor and discuss this with him. The only way to be sure as to what it is is to see your doctor. Its better to be safe than sorry.
