Hi and welcome to HCM.
This sounds like upper gastrointestinal bleeding
which usually occurs in stomachsuch as ulcers and erosions but can be found in duodenum
too. SOmetimes it is hard to evaluate the acurrate bleeding location because it can bleed for short time and then it is not visible. ALso you should consider some other cause of anaemia. The best approach is to take iron supplements
and blood transfusion
if neccessary and repeat endoscopic tests if anaemia persist. ALso check your clotting factors and haematological findings to see is there any clotting abnormality. WIsh you good health.