Forget about the B vitamin stuff. I take it every day, not a real biggie if you miss it, the multivitamin i have has plenty anyway. But that's not the point. You didn't lose weight b/c of lack of B vitamins. If your diet was in check and you increased calories post cycle, and you took supplements as well to help maintain the mass, and your style of training you kept the same... only thing i could think of is your body's natural testosterone production may have been low post cycle and b/c of the hormone imbalance you lost most your gains.