Hello dear,
Since you have ulcers, they act as a source of blood loss in your body.
Moreover, they also prevent the absorption of Iron, Vit B12,
Folic acid & other essential nutrients necessary for blood formation.
As the ulcers are healed, your
hemoglobin status will start improving.
Till then, the requirement needs to be met with iron infusions.
So, your doctor is very correct.
Kindly follow the treatment as advised.
There is no need to worry, you will be fine.
Wishing you a good health.
Take care.