Earlier this year, I hired a new running coach. I’d done my first ultramarathon the previous fall, a 50K trail race, and wanted to do it again, but better.

Two days after I hired him, my dog died.

Of course I expected to keep running. I’d used it in the past to grind down feelings of hopelessness and frustration and loss. Running got me through bad breakups, being self-employed during the Great Recession, even the death of a grandparent.

But this was different. This was a flattening. This was losing my companion, one who had been by my side for 11 years.

Emily, a Jack Russell terrier with a persnickety temper but a heart of gold, didn’t run with me — she couldn’t because of a heart murmur. But I adopted her before I ran my first 5K, so she was part of my routine: pet her goodbye before I left, let her lick my legs when I was done, and often, after a hard workout, tuck her little 12-pound body next to me under a big maroon blanket so we could both take a snooze and be refreshed for the rest of the day.

I tried to stick to the schedule my coach made for me. I’d tell myself that this time it would click, this time the run would be a reboot, that this time, it would be worth it to get out of bed and put on the clothes and run myself better. I’d try, struggle through easy workouts, then open my front door and reflexively look to where my dog would be waiting for me, cocooned in blankets on the corner of the couch, and then I’d crumple because of course she wasn’t there.

I made it about a month, quitting in the middle of what should have been a 12-mile trail run in Valley Forge National Park. I startled a deer, then stopped to walk, then buried my face in my hands. Why am I out here? Why even bother?

So I didn’t. Instead, I focused on another big change: I sold my house. That meant disassembling my life and packing up the things that had surrounded me in my house for almost a decade, including my dog’s favorite toy and blanket and the sweatshirt I was wearing as I held her when she died.

I found a short-term rental next to the ocean in Cape May, N.J., and instead of running, I wrote, I read and cross-stitched while watching old movies on Turner Classic Movies. I let myself sleep. I gave myself permission to do very little because sometimes just getting through the day and remembering to eat took up most of the energy I had.

The sun grew stronger, the days longer. I started walking: first, short walks on a still-cold beach. Then to the grocery store. Then the gym, where I told myself to do something with weights for 10, then 15, then 20 minutes.

I ran — slowly — to do errands instead of logging predetermined miles: getting cash at the A.T.M., running to the post office a mile away to mail a bill instead of dropping it in the mailbox near me.

I did this to remind myself that I could still do it, and entered a few races: a 10K, a 10 miler, two half marathons. Sometimes those races were the only miles I’d run that week, and I often felt lumpy, fat and slow.

I finished far from my best time at those races, but I finished. They were small wins, but I took them, and treated them as the victories they were.

This summer I hit the road. The plan was to see the 18 states I hadn’t been to yet, aiming for the goal of visiting all 50 by Labor Day. I hiked a lot, but I also ran in Oklahoma, New Mexico, Hawaii. I ran a firecracker four-miler in Denver on the Fourth of July, then won second in my age group in a women’s race in Boise, Idaho, a few weeks later.

The day after that race, I walked into a Boise animal shelter and there, sitting in a cage in a row of cages of very large dogs, was a petite young lady with brown eyes, a tawny face and a melody of browns and beiges in her coat. She looked like a cross between a German shepherd and woodland sprite, though most likely she’s a cattle dog. I adopted her and named her Annie Oakley Tater Tot.

I put my 50-state quest on hold and drove her back east. I am still grieving Emily, but this new dog has made me so happy: the way she tries to honk my nose when she’s excited to see me, and how she lies flat on the ground when I go to put on her leash. She has two: a regular one for her regular walks, and one that loops around my waist when I take her on a run. She’s still new to it, so she joins me only for the last few minutes of the runs I’m doing. I’m training for my ninth full marathon, which I’ll run in October in Boulder, Colo., where we’ll be moving in the fall.

She’ll also be coming with me to see the last three states on my list. After that, who knows. For now we’ll run, we’ll love, and for the next decade, and hopefully longer, embark on a grand adventure together.