paternal grandmother is scary

I have a very strange life at the moment. I'm a mom of three amazing children, but I'm divorced from their father. I found myself pregnant with a fourth baby in February by my boyfriend. My boyfriend never wanted children, and I was done having babies, but we both plodded along on this seemingly pre-set course of parenthood. His mother was insanely excited ( and I mean that literally ) from the beginning because he's an only child, and has treated this as if it's her last chance at redemption from some unknown sins of parenthood past, and has taken complete ownership of this baby from the beginning. She's a very manipulative, controlling person and has passed her judgements on my birth choices, names we chose for the baby, sleeping arrangements, etc. on down as if they are from God's very mouth, and who would know better than a single mom of one adult child that practically raised himself? I digress, sorry. It became evident to me that the stress of not knowing how to raise a baby alone, or even with support from my boyfriend was mounting ever higher, and I couldn't sleep. We were growing apart, bickering, and he was becoming more distant and reticent to participate in my pregnancy. I said from the beginning that I didn't want this baby. I disagree totally and completely with abortion, though, and so had made myself continue, alone and nearly abandoned, steeling myself for a life of total hurt, sadness, and heartbreak. I knew my boyfriend didn't have it in him to be a father. But he really was trying. It came to a head one night when he sent me a very honest and transparent email admitting this to me. I knew, in that very moment *CLICK* what I had to do. As a child of adoption, myself, I know how amazing and beautiful a gift it is to release a child into a childless family. I had already been told of a family who desperately wanted a baby, and had been waiting for years for it to work out for them. My boyfriend's and my own relief were instantaneous, and the family is wonderful and excited. The problem is... his mother. She's going beyond bizarrely inappropriate. I had to have her blocked from my cell phone to stop the crazy harassing texts, but she won't leave him alone. Recently she got ahold of one of his roommate's phone numbers, and started texting HIM. She's threatening us with all kinds of ridiculousness, and wants to feel as if she's in the driver's seat for this one. We're both completely bona fide, established adults. I have a family of my own already, and my own parents are completely supportive of this decision. I don't live in the same city as my boyfriend or his mother, but she does know where I work. I can disappear for the last couple months of my pregnancy, but I have three children who would be devastated if I did. Is there actually anything that she can do? Is there any action we can take to stop her harassment? PLEASE HELP... if you know anything, please let me know.