Rectal Bleeding - need help

Internal bleeding, bright red blood coming from rectum. Bleeding mixed in with stool, after stool, or bleeding without stool.
This bleeding happens occasionally (as in not always evident), is becoming more frequent.

Bowel movements irregular, soft, formless and liquidy, does not appear to be straining because stool is soft.
But bowels seem to struggle with releasing. Have one bowel movement a day but only tiny bits slip through.

Other symptoms:
Lower abdominal pain, lower back pain, like where the small intestine is, bowel pain, sharp pains, but these pains all comes and go. Bleeding and bowel movements are completely painless. Constant bloating. Abnormal weight gain, 50 pounds in 2 months.

Past history of eating disorders, such as laxative abuse, anorexia, bulimia, which have caused digestive problems and possible bowel problems. Have been recovered and healthy for about 3 months. Eating healthy, regular, and exercising.  

Went to emergency room today, had a gloved finger shoved up there. Haemorrhoids, fissures and tears are ruled out. There was nothing abnormal up there. They just sent me home. I am to schedule an appointment to have a surgical scope done. The waiting list could be months. But they gave me no answers. Nothing else was done. For my own safety i need to know what else to do, what other tests i should get done, and what these symptoms could be. What is wrong with me? Can anyone help me out?    
  

[Morecambe]

You have done the right thing by seeking medical advice and a colonoscopy is a relevant further test.

For additional background google rectal bleeding and click on to one of the many sites - the Medicinenet site is particularly informative.

regards
Morecambe