About to loose my freaking cool

My mother inlaw lives next door to us. She comes in all hours of the day at random times. Wakes the baby up, comes into MY bedroom while the baby and I are trying to nap. She will come in and speak Spanish to my husband which I think is so rude considering I don’t speak Spanish at all and that this is my house. My sister inlaw will just walk in and leave the door half way open and I’m scared my cat will get out. She will follow me around the house and stare at me while I feed the baby, and change her. They are making it really hard to bond with my little love because I’m always on edge that they will just barge on it and ruin the moment. I can’t even hide out with her in our bedroom because they will just come right on in even if the door is closed. When I try to talk to my husband about it he gets really mad and defensive. I don’t know what to do.