zoogirl,
I had the exact same thing happen. I switched underarm products, soaps, shampoo, mouthwash etc. I think part of the problem was constipation. Got that under control but co-workers still complained loud!!
Then I caught a whiff of my hat....then my pillow...it wasn't my hair! It was my scalp!! REALLY GROSS if I didn't wash my hair for a day.
Long story short: sulfur soap and antibacterial shower gel for a week cleared it up. Really dried my hair but I just put it up for a week. I use sulfur soap once a week to keep build up down. Good luck! May it be an easy solution for you.