book suggestions that helped you cope with grief?

my rescued kitten died. I feel so sad. Idk how i can handle the grief and guilt of losing a pet. I blame myself. I have many faults that keep me up at night… It was always flashing back, the way he wanted to cuddle with me, but I was very stress… there are moments i feel i neglected her. I don't know how to forgive myself. please help me. every morning I wake up with a heavy heart, missing her. I didn't give my best with the kitten, and I'm so regretful. I'm very sorry 😞