How to set boundaries with mother-in-law?

My mother-in-law is very helpful, or at least tries to be. She is also very excited for her first grandchild. Too excited.

She will walk into my bedroom when I am in the middle of feeding or pumping when I’m in nothing more than a bathrobe and boobs out. She won’t even knock or ask if she can come over, she just shows up.

She acts like my son is her son, and doesn’t listen to me at all. Quick examples of things that have also been bothersome. My son had breastmilk jaundice, She called my son’s pediatrician freaking out and crying to ask questions about his health. Then one morning at 7am she sent me 3 texts and left a VM with her crying telling me to take my son to the pediatrician ASAP because he looked more yellow to her when he had an appointment coming up 3 days later to be rechecked and get his 6 week shirts. He was actually much better that day, jaundice travels down the body then back up, so what she was seeing was it going away, but she won’t listen to me. I work in a Doctor’s office. She was also a nurse, but not for over 30 years.

I try very hard to be kind and I don’t want to hurt her feelings, but she stressed me out so badly 2 weeks ago that I got mastitis and it recurred once already. I finally talked to my husband to tell her to “back off in a nice way,” but she doesn’t get it. I even resorted to closing my door and putting up a do not disturb sign when I feed my son in our own bedroom in our own house. She STILL comes in! It makes me feel SO uncomfortable and I don’t know what else to do.

It’s been especially hard with the holidays. With Christmas coming, I need help to get her to stop. Any suggestions are welcome.