Any supplement with any niacin in it at all gives me problems. I wound up taking all my B vitamins piece-meal, in their most active forms, because I couldn't find a b complex with no form of niacin in it whatsoever.
Taking piece-meal turned out to be very effective. And now I'm fairly stabilized I don't seem to need much of the B's besides what I get in my food. Except for the B12's and methylfolate, of course, and I'm still reducing my doses of those to what I hope will be low dose for lifetime maintenance. I do drink milk and eat Ezekiel bread, though, which I know some people can't do. Those are good food sources of B's, and they may help me.
So, if your're scared of your B-complex, you might consider trying piecemeal. It's a little more expensive, and there is a little bit of a learning curve (figuring out what the most active forms are, what might be best for you to try, etc.), but I found it worth it.
Good luck, Adly!