loosie gave you a lot of possibilities for what's happening with your horse in his new situation. It'll be your challenge to read the horses & see what's really happening! Please don't take it personally; no need to feel dismayed!
The relationship is priority, then the horse will "catch" you. Change it up, think "relationship", not "catch", meaning, don't try to catch, but spend a good half hour in horse's space just sitting, & let horse's curiosity draw it to YOU. Don't even be eager to pet him, just allow him to make the gestures. It'll change the game.