Asking visitors to call before coming over?

Am I being ridiculous in not opening the door if I'm not expecting anyone? The issue is mainly my in laws, we live 2 doors down from them which is an issue we need to fix when we can afford to move. My MIL and me do not get along, she has made obnoxious, snarky comments to me since our son was born and I'm over it and done being bullied by her. She gives me anxiety and just being around her sucks the positive energy right out of me. I'm 6 weeks pregnant with our second (she doesn't know because she's nosy and would tell everyone when we want to wait til the 1st trimester is over) I'm crazy emotional and she doesn't call when she wants to come see our son. I'm pretty sure she knocked on our door today shortly after we got home but I totally took the baby and hid. The barking dog and my rig out front were proof I'm home, but I'm done with her making me feel inferior to her. My husband sides with me and has let his mom know that she's not going to drive a wedge between us, when she accuses me of coming between her and her son, and how he started acting like an a-hole when we got together. She has a thousand excuses for her behavior, none of which are her fault. I will deal with her only when I have to and when my husband is around.