Gastroduodenitis and persistent streaks of blood. What's wrong?

My GI ordered an upper endoscopy as I have been bleeding streaks of blood mixed w saliva for 8 days now. Today, I had the scope and the result was gastroduodenitis. A day and a half ago, the bleeding stopped as I had constipation. Today, I woke up w severe cramps and watery d. I had to fast for 8 hrs before the scope and so I couldn't take Imodium. Because of the stricture of my rectum, my surgeon told me yesterday that it is 3.5 to 4 cm long, so I have to strain even if it is watery d and accordingly blood returned. It reached the extent that when I was on the examination table, I asked my GI to go to the toilet and he told me that I was going to be sedated and won't have the urge.
When I woke up, I rushed to the toilet and the bleeding of the esophagus was still there. When my GI was discussing the results, he mentioned that this could be caused by either straining or vomiting and the throat could be wounded. As a result, Zofran im injections were prescribed for 3 days and Imodium to stop d. But blood is still there and he insists that there are no wounds in my esophagus. Did anyone have a similar experience? Having blood all the time in my mouth makes me feel nauseated.
Should I live up w this until the wound heals or should I see an ENT?
Any suggestions are highly appreciated.

Bill, thank you very much. Your opinion could be right as the stool is never that dark as it would be had the stomach been bleeding. The thing that makes think that the origin of blood is deeper is that it is always accompanied by excessive saliva but still the gums could cause this. I'll ask the GP to prescribe the suitable X-ray to investigate this.