I would look more into anemia. One of the downstream problems with low hcl acid is anemia, and this is worse for females.
For the hcl acid pills, start at your current dose and keep raising it until you have a slight burning and then back off. You may still be low even though you are currently? supplementing and feeling better.
For b12 I don't think that injections are a fully solution even though they may be helping, so I'd look into food sources for that too, clams, yeast, red meat, liver.
For the anemia try molasses, calf liver, dark green leaf vegetables, and the herb 'yellow dock', which has been known to also somehow correct the underlying cause of the anemia.
Homeopathy and schuessler salts are popular in europe so look into calc phos and ferr phos for the anemia.