You should try taking the Pantothenic acid. I got pantethine because it's less processing for my body, but that one didn't feel suppressive at all, in fact it felt stimulating, so don't take too much at first because you might crash later. Every time I take it, it's still the tip-of-the-toothpick amount. You should start small with that one too.
By the way, maybe you should lower the amount of magnesium you are taking. Even though 400 mgs is the RDA, I only take 50 because I'm probably deficient in all minerals and taking the RDA of only one mineral is going to jack up the mineral balance ratio. And sometimes that does happen, even with only 50 mgs, so I don't take it every day. Build up the stores slowly. But not too slow, as I'm learning, because there are consequences to that too.
I don't know the RDA or much about vitamin E, but I'd apply the same principle.
With the thiamin, I'd probably take a tiny amount one day, take another b vitamin the next day, etc. Mix it up throughout the week until you start taking two kinds of b vitamins a day on some days, etc. Work up to it. That's my plan at least, although my mental deterioration might scare me into speeding it up and taking more risks.