Metallic taste

9 or 10dpo...a few days have had metallic taste in mouth. Period not due for 6 days. Anyone have this and not end up pregnant?? It's not strong where I can't eat anything but it's noticeable and it could be like 2 hours or half a day. I've been on my vitamin for 3 months so I'm used to that, I don't believe it's that. Just curious !