It's been three years, but it was only a few weeks ago that I was able to pull my old dog's bed out of storage and look at it without crying. Otis wasn't just my dog; he was my friend, my workout partner, my first baby and my stalwart protector. In our 14 years together, Otis was there for me through the birth of both of my daughters, five moves, one tarantula infestation and countless bad haircuts, which he endured without skipping a beat.

It's no wonder his death left a giant black lab-sized hole in my heart. Anyone who has ever lost a longtime pet knows this feeling, and many also understand completely that the loss of a pet can be as hard as the loss of a close friend or family member. Here's why you'll never forget a loyal dog:

1. You may be closer to your dog than you are to some members of your family.

A 1988 study published in the Journal of Mental Health Counseling asked dog owners to create a family diagram placing all their family members and pets in a circle whose proximity to them represented the strength and closeness of their relationships. Not surprisingly, the participants tended to put their dogs as close as or even closer than family members. In 38 percent of the cases, the dog was closest of all.

2. You dog's world revolves around you and your happiness.

If there's one thing that your dog loves even more than chew toys, cheeseburgers and chasing squirrels, it's you. His world literally revolves around you, and he will do anything at all to make you happy. There's no other being in the world that will give you as much nonjudgmental love as a dog will.

3. Your pet is your stress reliever.

A study published in Frontiers in Psychology found that contact with pets can help to reduce stress by lowering levels of stress hormones, calming the heart rate, and even elevating feelings of happiness. Losing a pet is like losing a friend, counselor and yoga-instructor all in one.

Happy old dog All it takes is a quick scratch to make your dog's day. (Photo: Wisut/Shutterstock)

4. Pets appreciate your every effort, no matter how small.

At the end of the average day, I will have cooked, cleaned, run errands, worked, shuffled kids from school to after-school activities and home again, paid bills, worked some more, rotated laundry, and organized a playdate , a fundraiser or a closet all without anyone in my household even noticing. Yet my two current dogs (Henry and Honey) are seemingly overjoyed by any effort I make — no matter how small — to keep them fed or happy. It's easy to feel like a superhero when you see the love in your dog's eyes reflected back at you.

5. Your dog understands you.

Honey, my energetic running partner, knows well before I reach for my shoes whether or not it's time to get ready for a run. Henry knows when it's time to play and when it's time to dog pile on the sofa for popcorn and a movie. And it's not just your mood that dogs understand. New research shows that your dog probably understands much of what you say — and even the tone of voice you use to say it.

6. Dogs are loyal to the bitter end.

For all of the good days we had, my boy and I had our struggles, too. Yet Otis never judged me for the days that I forgot to feed him (or myself,) or when I walked around the house like a zombie while caring for a new baby. He didn't object to squeezing into the middle console of a two-seater truck when we moved across the country. He forgave me for all of those missed walks and harsh words when I struggled to juggle the demanding tasks of caring for a growing family.

Yet, when I needed him, he was there, without fail. It was Otis who sat by my side as I rocked a colicky baby through countless sleepless nights. When the Twin Towers crumbled to the ground, I wept silently into his collar. When a close friend lost her son to cancer, Otis walked with me around and around the block as I struggled to understand the meaning of life.

7. Even if your dog is no longer with you, he wants to comfort you.

Your dog would never want you to be sad — even if your sadness is caused by his loss.

Animation student Shai Getzoff captured this sentiment perfectly in his short film "6 Feet."

"I based this story on my beloved dog who passed away last April," Getzoff commented in the film notes. "She spent 15 and a half wonderful years with me and my family. After she passed away, it took a while getting used to life without her. It felt like she was always around, when in reality she wasn't really there any more. This, for me, is a way to say goodbye."

Grab a tissue and give it a watch.