Dan, I understand how you feel about Kirby when you say you can't imagine having another dog like her. No dog will ever be able to replace her or make you feel the same way you do about Kirby.
There are 2 special dogs in my life I feel exactly that way about. The first dog was a white female Husky named Sheba. Sheba was about 6 or 7 years old when we rescued her from the pound....my parents got her for me when I was only 3 years old since I loved dogs & Dad didn't like us paying lots of attention to his hunting dog that was his best friend. Sheba was MINE....my responsibility to take care of & love....and she was such a sweet adorable dog with so much love. Mom told me before she passed away that Sheba would tolerate me tugging at her ears without even whining; I personally don't remember that, but she did; so that says something right there. And Sheba would nuzzle me in the morning & wake me up & get on the bed & give me lots of kisses, I have so many good memories of her & how adorable & sweet she was. However, unfortunately, the reason she was given to the pound, we found out, was that she had severe arthritis in her joints, & her veterinary bills & medicine turned out to be extremely expensive. When Sheba was 13 years old, she was in so much pain constantly, we couldn't bear to watch her suffer, so we made the choice as a family to put her down. I cried so much for a good couple of weeks after she died, I always think of her still to this day & I know she is waiting for me in heaven.
The other dog that was special to me was our family dog Sarah, that all 3 of us kids were responsible for. Sarah was a black lab/German shepherd mix, but she looked like a lab, just that she had a white patch on her chest & rough hair on her back like some german shepherd's have. We got her from the pound when she was 4 months old & still very small. But she grew up VERY quickly, & was a very rambunctious dog with tons of energy, & she never tired of roughhousing, swimming in the pond, or throwing balls for her all the time. And she loved camping....she loved exploring in the woods & sometimes she brought back a squirrel or chipmunk as a prize to show us. And a couple of times she got stung by porcupine & got a mouthful of quills, I guess she didn't learn her lesson the first time & was still curious LOL. She was always going into the forest behind our house, & sometimes she would be gone more than a day, she was a very adventurous dog with such a happy spirit & so loving. My favorite memories of Sarah is every day when we came home from school, she would come running to the door, & the I opened the door she would bark & start wriggling all over the place as I petted her, & her tail would get as hard as a baseball bat....it would hit your leg & give you a good gentle thump. And when we watched TV in the rec room in the basement, she would come jumping up & lay on top of our laps at night. And on weekends, she would nudge my Mom & Dad's room door open & jump on their waterbed, start licking them & wake them up real early in the morning, usually around 6 or 7 am. One time Dad outsmarted her, though, because he was determined to sleep in & she wasn't able to get thru the door....we found her with a sad look on her face outside their door, she felt like she had been rejected. We had a good 12 years with her, when Sarah was about 11 years old she started developing arthritis & wasn't as active anymore, her spirit was getting tired. About 8 months later, we found out she had cancer, so we made the decision as a family to put her down & bury her in the backyard. I will always miss her & think of her all the time, I know she is waiting for me up there & I know she will be jumping all over me when I pass away & we meet again.
Dan, whatever you do, hold all those good memories of Kirby in your heart, & try to move on & be happy. Kirby wouldn't want you to be sad, she would want you to move on & make happy memories & have good times in your life, even if another pet never entered your life again. Now, about having a child....just whatever you do, think long & hard about it....remember you will be making a lifelong committment to being a father & loving your son or daughter, & showing them everything there is to know about life. It would feel wonderful to be a parent & have the love of your own flesh & blood child, but it is such a huge committment, just make sure you can give all your energy as a father & be the best father your child deserves. And of course, make sure you find a good woman to be your child's mother....after all, you will have to live with this person being involved with you for the rest of your life as you both strive to be good parents for your child....make sure you are compatible & can live with this woman in your life for a long time to come. I do know though that you will make an excellent father, if you do decide to have a child.
I will keep you & Kirby in my prayers, & will be thinking about you....Rob