Putting my pup to sleep in a couple hours

When I was seven my parents and I got a puppy from the pet store. I named her Jessie after the character from Toy Story. This is a picture of her from the night we brought her home. I still remember holding her in the back seat on the way back from the mall. She was my best friend growing up, I didn't have any siblings but I always had [my puppy] (http://i.imgur.com/38ZxfLB.jpg) to cheer me up. She's 14 now, and up until just a few weeks go she was fine, here's a [picture] (http://i.imgur.com/SaaEBIl.jpg) I took of her begging for people food as usual and another of her trying out her new bed. But as of last week, things started going downhill, she wouldn't eat, her back legs started giving out, she was hesitant to walk, and shaking. We took her to the vet, they said she had kidney disease and wanted to keep for for the week for keep an eye on her. The day after Thanksgiving they let us take her home and they said she was doing better, but she was worse if anything when we took her home. We took her back to the vet on Sunday, and today I got the call from my mom that the vet thinks its time. I'm heartbroken that in a couple hours I have to say goodbye to my baby girl. I grew up with her sleeping in my bed, and her meeting me at the door every time I visited from college. She used to love helping us open presents by tearing off the paper, and even with all the toys we bought her we could never beat the tennis ball. This is the last picture I took of her. She wanted to sit in her favorite spot but she couldn't get up herself and I didn't want to her to jump down and hurt herself so I spent last saturday sitting with her so she could look out the window and nap and bringing her water and food. It's been an emotional roller coaster not knowing what would happen the last weeks. It's good to know she won't suffer any more but saying goodbye is going to be really hard.