Prenatal causing baby to be gassy?

Hi all - my daughter is 6 weeks old and I exclusively breastfeed. She always has terrible gas that seems to cause her discomfort. Her ped had me stop eating dairy but it's been 2 weeks and doesn't seem to have helped yet. However... I forgot to take my vitamin 2 days in a row (rainbow light) And she was SO much less gassy. Has anyone else experienced this? Not sure if it was coincidence. I don't want to stop taking vitamins all together so if you have a specific one that you think would cause her less gas, please comment. Thank you in advance!!