You are a good man. What a loss. I am sorry, horses can be so special. I believe horses and other animals can see into the hidden, spiritual realm at times. I think that is the case in a situation like this. The Lord cares for all His creatures.
Did you know that when they had the big tsunami a few years ago in Indonesia that wiped out everything. I heard that before the water got there all the animals headed up to high ground, they stopped just above where the water reached. Dogs seem to know when an earthquake is coming. This horse you loved was likely comforting you because it knew what was happening and knew that everything was going to be OK... or more likely you comforted one another. Yeah... I believe that. Horses are REALLY smart and loyal.
Another horse story, Confederate general Bedford Forrest's horse hated Yankees. After the war between the states there is a story (in his biography) of his horse seeing a man in a blue uniform down the street... the horse charged the man... it probably wasn't funny at the time but I cannot help but chuckle now...
If you had a bond with a horse, you had a bond and you now have a loss. Pass it on, it is a fitting way to pay tribute to your loyal friend. Be a loyal friend to another.
Thinking of you.
Julien