Usually it should be ok to donate blood every 2 months, as your body should produce it back and more within that time frame. Every time you donate blood, your iron levels go down (and therefore your ferritin level, which is a marker of iron stores in your body).
The fact that it is <12 is very significant, and you should not donate blood, and take iron pill supplements. If despite taking iron supplements
and not donating blood your "ferritin level" and iron stores remain low, you should actually get more testing done to explore why is this happening as this is not normal. It could be that you are losing it microscopically through your gastrointestinal tract (in the stools, and not necessarily you will have seen XXXXXXX blood in stools); another common problem is that you are not producing enough red cells.
So in conclusion, my advise: don't donate any more blood; take iron supplements by mouth; recheck your blood tests in 1-2 months. Follow up with a primary care
Also, you mention you have "severe stenosis". If this stenosis is from the Aorta
, then being anemic (which is common if you have low in ferritin / iron ) is very XXXXXXX
hope that helped, let me know if you have any further questions.