Help with my mother in law...

I’ve never really loved being around my MIL, but since having my son I cannot stand her. It began with her deviating from my birth plan and being in the delivery room. She is constantly questioning anything my husband or I do. I am exclusively breastfeeding and she does not like how my sons bowel movements look and how frequent they are and is constantly advising us to just switch to formula and that “my milk isn’t satisfying him”. The other day she stated I am only STILL breastfeeding (son is 4 months old) out of spite so she cannot feed him. She told me if I want to continue breastfeeding I need to pump so she can bottle feed him when she sees him and even went as far as giving us money for Christmas to buy a garage freezer to store pumped milk. If our son cries, she automatically says he’s hungry, even if he just ate. I am returning to work soon and my mother and her will both be watching my son one day a week each and he will be going to daycare the other three days a week. The daycare is very close to my office so we will have time together during the commute and I can go see him on my breaks. My mother in law is so upset that we’re not letting her watch him full time. I am very adamant that she not exclusively watch him since she doesn’t interact with him, just sets him in front of the TV on the floor and overfeeds him. I have been very respectful but my patience is running out. She is no being respectful of us as parents and I’m afraid I’m going to snap on her and say something that will create unrepairable damage.