I killed our hamsters 😢😭

My boyfriend and I got two adorable hamsters about 6 months ago from a family member. Well my boyfriend fell in love with these little girls. Well I decided to be an idiot and adopt a cat a month ago because I wanted a cat and thought adopting it would save her life. Well today my boyfriend and I went shopping today and we came home to our hamsters dead. My fucking cat killed them. I know I can't be mad at her because it was her instinct but I'm mad at myself. It broke my boyfriends heart. I cried so hard those were our babies. I thought that because she hasn't ever gone at them before that we could actually leave the bedroom door open for her to sleep in the closet like she usually does when we're home. I hate myself so much for doing this, and putting those poor little babies in that kind of torture and horror. I will never forgive myself. It's tearing me apart right now. Idk why I ever thought of bringing a cat into the house while we have hamsters.😢💔