Pet illness and loss

Does anyone know how on earth to deal with your pet passing away? Just found out my baby has cancer in her throat and lungs. We have to put her down in a week. Ive had her for 13 years. I’ve lost humans and have gone through so much shit and trauma in my life but this is the one thing I don’t know how to handle. Idk how I’m gonna live without her 😞🐾 she seems so happy and she’s eating plenty but her respiratory rate is so so high for a dog her size. I can’t believe she’s been suffering with this