You should try taking omega-3 fatty acid supplements. I have read some case studies where they increase antibody to Hep B.
The only thing you can do is check to see what changed in your diet.
Start taking vitamin D and Zinc. They should help with the situation.
Take at least 5000 IU of vitamin D.
yes you can get back to hbsag positive if it has been achieved by nucs only.take high dose hbig (hbsab immune globulins) as soon as possible and retest hbsag and hbsab, if you can afford it dose should be determined by response on hbsag/hbsab.you should also boost your immune function by taking 10.000iu of vit d daily and keeping vitd25oh blood levels around 100ng/ml.you can also take zadaxin and reishi/shitake/maitake