Going to respectfully disagree here. Even if you work full-time, adopting a dog is a great thing to do. A dog spending 8 hours waiting for you at home is much happier than sitting in a kennel in a shelter or waiting to be euthanized. And dogs are great for getting you out for that morning or evening walk/jog to lose weight. Many dogs are pretty low energy too. You can absolutely find one to fit into your lifestyle.

I work 60 hours or more a week and I have my own dog and I foster a dog temporarily. I suffer from major chronic depression and PTSD, and the one thing that keeps me sane is the dogs. If I didn't have them in my life, I would likely break down entirely. But they bring me so much joy, I am able to cope with work and all the other crap in the world.

It's normal to grieve over a pet, and maybe take a day or two off work, but I think if your grief for your pet is keeping you from work entirely and you have to quit your job, then you need to see a therapist. Also, there is nothing wrong with rescuing another pet to honor the pet you have just lost.

I have also been on the hiring side, and I will say that age never mattered much to me, it has to do with experience, energy and ideas. As you get older, you have to make more and more an effort to keep up with technology and social media that younger generations are using or you will become irrelevant. It's a hard truth, but it is true. If you work in marketing, and you can't stay up on the latest marketing systems, you aren't going to be hired.

Look into getting some counseling, and when you have had enough time pass, maybe look into rescuing another bunny to honor the one you lost.

Good luck,
seesaw