Afraid that my BFF will go nuts if i get pregnant

Well, there is no need to beat around the bush so i will try to be as honest as i can. A very good friend of mine or rather somebody i had assumed that was my friend has turned out to be a pathological liar. Everything started off with my husband and i deciding on a third baby. Since i had major issues during my last pregnancy which inlcuded preeclampsia and Hellp Sydrome we even terminated a pregnancy last year. I am a high blood pressure patient and hitting 35 here pretty close but all that is just side line information. A few days after i had told my friend that my husband and i wanted to try for another child she out of the blue told me a week later that her period is late. Eventually she claimed to be pregnant. Neither my husband or myself have seen her so called boyfriend or any ultrasounds.... I even asked her if she wanted to have some of my older maternity clothes she always changed the subject. Now last week, i told my husband" just wait, in a few days she will come and say that she had a miscarriage". Just like i predicted thats what she did. Told me that she had a miscarriage and of course not one medical document....

I am at a point where i worry about my safety and the safety of the baby i might get pregnant with. There is no sense in confronting that woman, she is so confused she believes her own lies. I guess what i need help with is, do you guys think i am over-reacting by considering to cut off the ties with that woman due to my concern of her hurting me or the baby once i do get pregnant? Honestly, i can't stand people that lie and keeping up a lie like being pregnant with all the stories about miscarriage etc is serious. Am i being too harsh, or do you think that i am doing the right thing by removing her out of my life before she might or might not to something rather violent and drastic?