No I don't think the niacin helped at all, we have been through this before. No wonder you threw up, you took 8 multivitamin Centrum, which has some heavy minerals that can upset the stomach. You are instructed to take a large dose of B2 riboflavin or a multivitamin, not a large dose of multivitamins. Its not smart to take 8 of the multivitamins because I am pretty sure your Centrum has iron in it and iron shouldn't be taken in massive doses.

There's nothing you can do now but wait and relax.