I never got to say goodbye to my childhood friend

I was living alone for the very first time after covid restrictions lifted, and my job fucking sucked. My manager hated me and packed every hard job onto my shoulders, and if I fucked up even once she'd be on my ass for days about it. Rent was expensive as hell and the food was evern worse, and I had absolutely no friends aside from the few from highschool I still occasionally sent memes to. Couldn't even really talk to family about anything cause all I ever got was "Yeah that's adulthood. It all sucks, oh well." The only thing that kept me going was when I got the occasional two days off in a row to visit my childhood best friend, Duke. At the time of passing, he was a 17 year old Belgian Malinois who still acted like the energetic puppy he was when I got him at 6 uears old. He'd laze around all day, only to bolt up and come sprinting to me, tail wagging like a helicopter and those old, creaky hips ignored in favor of jumping up on me. He had so much gray on his muzzle last time I saw him, and I can still hear him barking in excitement whenever he'd hear me open the door. He always knew it was me. He never got excited for anyone else, even when a stranger came by to inspect or repair something around the house even though he was supposed to be a "guard dog". We always gave him shit for being "the worst guard dog ever" cause splitting he'd do is bark at peoole walking by and demand pets when stranger came into the house. Last time I saw him was about 2 and a half years ago, when I was heading back into the city from spending new years at home. I could tell Duke didn't want me to go, he just had that look in his eyes and he couldn't even muster the strength to wag his tail. He just looked so sad, but I had to go back to work. It was two weeks later I got a call from my father, said Duke had been having problems shitting around the house during the night, but when he woke up this morning, the poor boy was half laying in it and unable to get off the floor. He said practically overnight his health failed and he couldn't even pick him off the floor without being snapped at cause he was in so much pain. Said he was calling in a home visit vet to put him to sleep tomorrow, and that he wanted me to be there in person. I didn't go. I made the excuse that my manager would just say no, that she just gave me three days off for new years and that she'd give me shit for asking for a such a sudden day off, but I never even asked her. I was too scared to see my best friend, the only one I ever had that stood up to my father when he got angry at me for something. He once took the brunt of my father's anger and refused to let him into my room for me because of an argument. I couldn't stand the sight of seeing one of the only good things in my life die in my arms. I fucking hate myself for it everyday. I have the occasional dream about him, just going for walks or playing with him, sometimes I have a nightmare or two about the copious amounts of hair he constantly shed. Every dream I have about my best friend Duke just reopens the wound and makes me hate myself more about it, and I've never opened up about it to anyone cause it just feels stupid to be so torn up about my dog Duke after almost 3 years.