Are you homozygous C282Y (as in two genes), or H63D, or compound heterozygous C282Y/H63D? Usually with homozygous C282Y your Hb bounces back really well even with weekly or bi weekly venesections. H63D is not a high ferritin level absorbing gene in the long run.
If you are not those mentioned above, and only have one gene, you will not be able to be venesected often as your Hb does not rebuild fast enough, and technically, you don't have HH. Another marker is having a TS% higher than 45%. What is your level?
Flu or any infection/inflammation can make your ferritin sky rocket. But you are talking about having this problem after venesection. Being homozygous C282Y, I feel so much better after having a venesection, then in about 13 days the fatigue and body pain descends on me again.
By early evening my body is so fatigued it feels shattered and I get flu like symptoms which disappear as soon as I lie down. I have to have dinner by 5.30pm so that I can lie down asap. If I lie down before dinner, I feel dreadful, and do not want to get up. they say not to take vit C/OJ as it promotes the uptake of iron, but we need antioxidants too, and if I don't take my vit C daily, I end up with flu. So I take it hours later last thing at night after, hopefully, my dinner has moved past my duodenal.
Foods like tea, coffee, red wine, milk, cheese (dairy which contains calcium) are not chelators but are supposed to help reduce the uptake of iron. You need to drink them while you have your meal in your stomach, (iron is uptaken by the duodena) and end your meal with cheese or yoghurt to help reduce the uptake of iron.
Honestly I preach this (as read The Hemochromatosis Cookbook), but personally, I am wondering if this really works, for me anyway. I am so tired of being tired and weak. I am 'deironed', and my ferritin is brought down to about 34 after each 3 monthly venesection which seems to be my optimal level - when I feel best (for a few days anyway).
Symptoms set in immediately after having a hysterectomy in 1998, fatigue and pain was extreme. My dr took 9 years to diagnose and only after one of my hips broke up. I ended up having both hips replaced and have had so many health issues since because of having so much iron absorbed by my organs. But theoretically, being deironed, I am told that I should not have any more problems. Personally, I don't think that is true for me, nor many others who had such a delayed diagnosis.
I have found that I am worse in terms of fatigue when I eat anything with sugar or starch in it, i.e. cakes, biscuits, etc of course, bread, pasta, rice, potatoes in any form. In fact I feel toxic and I feel like a truck has hit me. It is hard to resist other people's home baked goodies - I just don't buy that stuff at all now. However, celiacs have to do it, so I should be stronger. They suffer worse of course. I found that I lost a lot of fat from around my waist and belly as a result because that is where the 'sugar' fat goes.
Having said all that I have not answered your question about increasing Hb! It just seems wrong that you are getting low Hb with HH. So perhaps the answer lies in my first question.