I am sorry you are dealing with this on top of the pain. Are you on any meds that could increase b/p as a side effect? You mentioned blood work but have you been tested for auto immune conditions? How is your sleep? You stated your stomach problems do you feel you are able to get proper nurishment cause I wonder if that impacts not only the b 12 but being so tired? I am sorry I wish I had more answers rather then questions for you.
On a side note I live in South FL. FOr me cold and snow is worse but this is no picnic either. Just like you the heat and humidity is very hard so I am in doors mostly but the air conditioning bothers me. I have the vents directed at a certain angle so it does not hit my sensitive areas.