The blood can be due to internal bleeding or external bleeding through vagina, anus and mouth. There are many causes of bleeding like some diseases, cuts, trauma and accidents. Up to 10-15% loss of blood out of total cause no harm in healthy person. 15-30% loss of blood cause rapid heart beat, pale skin, blood transfusion is not required. Loss of 30-40% blood cause low blood pressure, high heart rate and disturbed mental status. Blood transfusion is required. More than 40% loss of blood can lead to death. After complete recovery from blood loss general health condition is improve. The other symptoms which you are mentioning might have other reasons. I advise you to discuss this with your doctor. For more details, visit bleeding.