I'm heavily broken and I don't know what to do

It's so hard to go home. Or even just to think about it. I cried myself to sleep last night. I just had a memory, and then it led to another and then another...before I knew it I couldn't stop crying and feeling sad. My mom is taking it really hard. I don't blame her. Lucy's her baby. She is the one who spends the most time with her since she's home all the time. It really hurts. And it hurts so much to see my mom upset. We are all upset. I haven't let anyone see that I'm upset yet. I've tried to not cry in front of anyone. But of course, that won't last long because that's not how I am. I can't hold things in when I'm upset. I knew this day would come. I've even thought about it in the past as I've realized how old Lucy's gotten. But I don't want it to be real. I don't want it to be now, and not like this. I think I'd rather not know. Even though the shock of it would be incredibly hard to handle, I think if it was unknown and she got really sick or just passed away in her sleep it would have been better. So we don't have to keep thinking about how she's not going to be here and how this is the last time for everything with her. The things you take for granted. The saddest day is going to be when she's no longer there to greet us at home. To bark at the doorbell ringing. To go on her morning walk. I could go on and on. She means so much to all of us, to me. Our lives just wouldn't have been the same without her. She's brought us more joy and happiness than is describable. It's so hard to say goodbye. Because I don't want to say goodbye. She's more than just a dog. She's a friend, a companion, our 6th member of the family. Actually, she's more like the center of our family. She really is just like another human. I don't want to see her suffer. To see her slowly deteriorate. We won't let her suffer too much. When she can no longer breathe comfortably, we will put her down. Mom wishes she will just pass away in her sleep. But I don't know what will happen, or when it will happen. I don't know if my parents know a timeframe or not, because they didn't tell us. I wonder if they do know and just don't want us to know because it's not long. I don't think it is long at all. I give her a month, if that. I mean, other than the cancer, she's perfectly healthy. She's having minimal complications so far, which is how we found out. But the thing with cancer is it can progress so fast, and it's already spread throughout other parts of her body. There's nothing we can do for her except make her last days as enjoyable as we can. And luckily she doesn't know she's sick. But at some point, I think she will know. I've never been in a situation like this, at least that I can remember and comprehend. My grandpa died of cancer, but I was only 7 years old. My first dog, Princess, had cancer as well, but it was sudden and I was still young at 10 years old. The dog we got after Princess, Teddy Bear, died unexpectedly not even a year after we got him from a heart attack. And that's what led us to Lucy. Lucy is the dog that I've really grown up with. I loved the other two just as much, but with Lucy it's different because of my age. I remember everything, and did so much more with her. I just can't imagine life without her. It has been different ever since I went away to college, but I got my summers with her when I was back from UCF. And she's part of the reason I came back. Because I missed my family. And Lucy is a huge part of our family--that's actually an understatement. I missed Lucy and my cat Frosty. And this is where taking things for granted has come in. I feel like in the past few months there were times I could have gone home and seen her, but didn't. But there's no sense in feeling guilty. I can't change anything. All I can do is make the most of the time we have left with her. Which is why I will probably go home more often. And even when I really don't want to, I know I will feel guilty if I don't, because it could be the last time I see her alive. I know she knows we all love her with all of our hearts. She's had the greatest life a dog could ever have had with us. She was spoiled rotten. But yet, she remained the sweetest, most loving dog I have ever met. She wouldn't hurt a fly, literally. I don't think I could be there if we have to put her to sleep. We won't take her to the vet--my parents have arranged it so that her doctor will come to our house so she won't get scared (she hated going to the vet). But I remember being there with my cat Milo, and how it was so hard to see her lifeless body lying there, watching the life slip away from her. It was hard enough then, and I definitely don't think I could be there with Lucy. But at the same time I want to be there. I just don't want this day to come. But in the meantime, all we can do is just let her be Lucy and live like she normally does, only savoring every bark she cries, every look she gives you, and just being in her presence. Because soon, they'll all just be memories. Forever.