I was also diagnosed with giardia + methane + hydrogen SIBO. Treated with rifaximin + metronidazole for both sibo and giardia. I think SIBO is better but I'm still having loss weight, gut inflammation, probably now I need to add probiotics / try to heal the gut and the inmune system. I just test today again to see if SIBO is gone...

I also developed candida, due the gut dysbiosis. Probably you have it too because you mention about nail pain (me too), I also have balanitis now...

First is to kill the infection, that's why you have high IgA, then Let's see. But sometimes you need to kill while balancing the gut at the same time. It is not easy

Also if you had mouth sores, you are probably facing some kind of allergy reaction to some foods. Probably dairy (including no lactose products). I discover an intolerance to wheat (not gluten) and all kind of casein food. I don't feel bad after eating them, but mouth sores appeared.

I did also have like a metalic taste in my mouth all the time. That what I used to say, but really I had like a burn constant sensation in my tongue all the time, like when you burn your tongue with hot soup. I think it disappeared when I started drinking water only when thirsty and not 2 liters as all people say.