genuine question, how do we cope with our pet's death ?

I grew up with cats, and just this morning, I was kissing my sickly cat (he was still breathing at that time), and I told him "close your eyes, baby", and then I went to the room to continue my crying session to God, writing diary, only for my sister to come and tell me that my cat is dead. fuck idk what to do, I've had multiple cats before and each time they died, I literally went insane idk how to cope, I never learn how to, I cherish this one so much, like so so much, he was fine a few days ago, but suddenly got sick, and we already bring him to vet but due to the high cost, we can't proceed with a thorough treatment, I didn't even get to feed him his medicine, wtf am I supposed to do with the meds, I feel so useless rn bcz I can't do more for him, this is hurting me, he was the only one who comforted me when I cried about my exam, and future, now he's gone, truth is, I can still hear his voice clearly, he's such a bright and clingy child

how do I stop getting attached to this creatures, help this weakass person, please guys