I feel like a child. Am i over reacting?

Zainab • 2 early MC, 1 baby and another BFP hope this is my second rainbow baby
Ever since I had my baby girl I feel like I am in a constant battle with my mother in law. She always wants to give her water or some herb in water and whatever. My baby is exclusively breastfed and as a medical doctor I know she doesnt need anything other than milk not even water. My MIL knows i don't allow it but does it anyway. Today my baby was hungry and wanted to go to sleep. Instead of giving her to me she starts giving my baby water from her own water bottle. She does this repeatedly and goes on and on about how im horrible for not giving her water and "see how thirsty she is". She also mentions how she knows this is upsetting me (i was so upset) i told her yes i am very upset. I'm so upset I can't speak because I am being ignored and feel like I am a child who can't take care of her own baby. I feel humiliated because this is all happening infront of my father in law, brothers inlaw, sister inlaw and my brother inlaw's wife and my husband is silent. I have never had a fight with my MIl and never even cried infront of her before. So me bursting into tears (happens when I am very angry) and going home early without saying goodbey should at least upset them? Anyways no one stopped me, no apology no "let's talk this out I didnt mean to upset you". I was not disrespectuful, did not shoit or taise my voice. I said that this is upsetting me because I don't allow it and I am being ignored and I am her mother. I jist got laughs for that. Now my hisband is watching tv and I am in bed alone feeling awful. Sorry for the rant