Help me. Please😭

My hubby slept with this girl while we were broken up. One time. Ok. FF a year. I have given birth to our beautiful beautiful daughter May 2019. Today I received a message. (First ss) wtf? Ok... blocked after a few messages back and forth.. new account. Same thing. I finally figure out its the girl. Bc she has messaged me before. She’s trying to say my hubby knocked her up. Now. They had sex in March 2018. She gave birth in February 2019. No way. Even THE FATHER OF THE BABY HAS REACHED OUT TO US. Bc she keeps claiming my hubby is the father! She’s even filed for CS against my hubby!!!! But anyways. I’m really upset with this shit. My daughter was born with shoulder dystocia. Her humerus was broken bc they delivered her left arm first. Everyone is well aware of this.. her dad burps her sometimes because sometimes I simply can’t get her to burp! How could someone be like this? I blamed myself and still do for my daughters arm being broken. I carry that with me every damn day. Now I have her harassing me and making me feel like I’m a pos mother etc. bc she’s jealous my bf didn’t want to stay with her.. idk what to do. I haven’t been away from my daughter since she was born. Expect when she had an X-ray. Please I am breakin down here. Ss of the convos.