A shelter puppy who suffered the heartbreak of seeing each of his siblings ... the shelter posted a video to its TikTok page highlighting how Sawyer was "sad" and "alone" since seeing his family head ...

A shelter puppy named Sawyer has been left to watch as each of his siblings get adopted while he's left behind, hoping and waiting to get a forever home of his own.

Sawyer the puppy was having a hard time getting adopted ... the shelter posted a video to its TikTok page highlighting how Sawyer was "sad" and "alone" since seeing his family head off to forever ...