It is likely that you are aborting. Any bleeding through vagina during pregnancy is suggestive of threatened abortion. If such condition is associated with pain in abdomen, usually the abortion process cannot be stopped. Another possibility is the pregnancy somewhere else than in the uterine cavity - ectopic pregnancy getting disturbed. The commonest site of ectopic pregnancy is tube. It can rupture anytime causing alarming bleeding and requiring immediate intervention with blood transfusion and surgery. Such patient usually presents with vaginal bleeding and excruciating pain in abdomen. You should not waste time now. Please report to your obstetrician ASAP for management of the condition.