Can anyone cause us harm without the permission of Allah?

This is about my brother's wife. After their marriage, I began sensing envy from her side. I tried my best to manage it, but in my absence, she made harsh remarks about me, which slowly led me to resent her. She had been trying to conceive, but I became pregnant around the same time. When she learned about my pregnancy, instead of offering congratulations, she initiated a major dispute at home. During my later pregnancy stages, I stayed with my parents, and she continually stirred up issues for me. I avoided confrontation, trusting in Allah's plan. Sadly, I lost the baby during delivery. The pregnancy and baby were healthy, and the loss was unforeseen. I recall her coming into the delivery room and reciting something. My husband, mother, and mother-in-law were constantly making dua, and I assumed she was too, but her presence made me uneasy. I am in profound grief, but I accept Allah's decree. He blessed me with the pregnancy and He chose to take my child. Insha'Allah, He may reunite me with my lost baby someday. Today, it's been six months since the loss, and my mother discovered several taweez in her drawer, one containing my name, my mother's name, and our dates of birth. Recalling her reaction upon learning of my pregnancy, her behavior in the delivery room, and her hurtful comments after my loss, I can't help but wonder if she used sihr to cause this suffering. She prays regularly and reads the Quran, but she also frequently consults those who make taweez. What's gone is gone, but how do I safeguard my present and my family? Ultimately, all matters are by Allah's will, but did He consent to this pain? Why did this happen?