DD is 3 and has been pretty able to express an opinion about the taste of the milk from around 15 months. She maintains that the right is much nicer and preferred it from birth. Before my period she mentions that it tastes different and that there's less there. Have always had a slight dip in supply once a month since my periods returned at 13 weeks.
Could also be any cream/bubble bath/spray you've used that's interfering. DD was mentioning a weird taste for a few days and I eventually worked out that it was the bath soak I'd just bought so not my milk at all.