Losing my best friend, my favorite individual

My dog, was more than just a dog. He was like my son. I have had him since he was 4 months old and he just had to be euthanized on. April 12th around 12:30pm. The week leading up to it was extremely stressful and emotional. He had a bit of a health decline but nothing major. I did notice now and then he was wheezing and coughing but not much. But then the last week it was daily and sometimes for five minutes at a time. He was really starting to worry me. I got the opinion of a vet and they said they were pretty sure it was the muscles around the trachea, creating a ‘collapsed trachea’ but it just wasn’t fully collapsed yet. This is unfortunately more common in small dogs (he was just 7.5 lbs) and when I was told that I needed to decide if it was time due to suffering/pain/quality of life I was heartbroken. I gave him a couple more days but he was just getting worse. So I scheduled someone to come to the house on Saturday so he would be able to stay stress free.

I spent his last three days taking him on walks and outside as much as possible. Lying with him and holding him. I gave him lots of treats and made sure he was comfortable (he was in pain meds). I know it has only been a couple days but my house feels so empty and lonely. I feel so empty and alone. I talked to him all the time and took him with me so many places. He might have been an old man but he still was so active and had no other big health problems. He still played with his toys and ran around the house or chased bunnies in the yard.

Part of me questions if I did the right thing. Part of me thinks my questioning it is just my being selfish. So much of me just wants to curl up in a ball and cry. Which, honestly, I have definitely been doing on and off the last couple days. I’m struggling to find motivation to get back into my normal routine. I haven’t been eating much. Trouble sleeping. Not socializing/or wanting to. I am having such a hard time feeling anything but grief and guilt. Some part of me feels like I let him down and was supposed to do more for him, supposed to do better to prevent what happened.