Hi Branston,
I'll address the potassium first. If that goes low and you start having nausea, and itching andheart palpitations, and weakness and muscle spasms pop you out of bed in the middle of the night you will KNOW that you have low potassium. Often it comes on hard and makes you feel sick. The more subtle onset is a tougher call but not likely to need much. If healing turns on potassium often goes low on day 3 or so. Try 3 or 4 tablets with a large glass of water. If that releives a lot of the discomforts, then you have nailed it. Then you may want to try increasing the frequency of doses. That is to say 2 tablets 5 times a day is much more effective than 10 tablets once a day or 5 tablets twice a day. Smaller doses tend to be less irritating of the stomach.
What kind and how are you doing the MeCbl? Not all MeCbl is created equal. The best is rare, perhaps 1 in 10 or 20 brands. Same with injectable, qualitative effects are all over the map and change from batch to batch of crystal the pharmacy starts with. Then expsoure to light can ruin it either during prep or drawing and injecting..
NAC might have been canceling out everything you were trying to do.
The L-carnitne fumarate is often most effective but a few people find ALCAR most effective. Many have found that the brands that buy the Sigma Tau carnitine from Italy (Jarrow and Drs Best at least, in the USA) are most effective. A lack of LCF can stall ATP production.
Once a person gets healing started, there are lots of clues to follow. Getting it started is difficult sometimes. Usually it is a matter of working throufgh all the things that generally might prevent healing startup. That full list is near the beginning of this thread.
http://forums.phoenixrising.me/index.php?threads/the-stages-of-methylation-and-healing.21725/page-1
Do some reading. Of course everything you do or don't do is at your own risk. As the problem isn't corrected yet the right combination does not appear to have been found. It sounds like you are on the track to get things started becasue all the impediments can probably be worked through.
One thing I will say is that if you are not using the Enzymatic Therapy MeCbl, at least to get things started so you have a standard basis of comparison, you might wanrt to get some of that if you haven't been using that brand.
My ex-wife had more than a $1000 worth of tests plus a chest x-ray (new onset asthma, not unusual with onset of methylblock). The doc got it right with b12 and floate deficiencies. It's just that he prescribed folic acid and CyCbl. I know from previous testing and experiences that she has had lifelong folate problems. Her doc years ago when Metafolin was prescription only wanted her to take that but it was too expensive. Her current doc doesn't know that and of course there is no continuity of records yet. So I helped her get off to a good start.
She had a "viral" infection never identified the end of last summer, the same time I had the crash form the changed Jarrow. She has never recovered from it and been going downhill ever since. I don't know how high her MCV is yet because they called her with some urgency and said to get started immediately and the paper results would follow.
What surprised me is how hard and fast it came on from genuiely normal MCV to frank macrocytosis in 6 months and extremely low serum cobalamin. As with you first the correctable situations need correcting and later perhaps we can figure out why it happened.
Good luck and good health.