I'm not sure about the multivitamin, but IMO, you're right on track about the carb blockers. I tried them, and wasn't happy. All I got for my money was bad gas, and feeling I could go off-plan just as you suspected! Some will tell you they work, but they block about half of the carbs from starch (NOT sugar) and I've read they actually only DELAY absorption....

For sleep, if a tryptophan-containing snack, like turkey doesn't do it, I like chamomile tea. Also, a supplement called 5-HTP helps me sometimes.

Good luck, and welcome.