Lately my horse has been anticipating things more. I'll be walking around my arena and when I turn to head back towards the barn he'll want to speed up. I'll stop him and back him up, then make him stand a few seconds when he does this. He also sometimes tries to drift toward the gate or another horse in the arena, especially if the other horse is standing somewhere in the arena. He will also especially try to speed up after we've trotted or cantered, like he gets worked up. He'll be walking fine, then I can feel him fall onto his forehand and he'll start slow trotting or jigging. He'll try this for a while, then he'll just walk. Today I was riding him and we had our mare and foal out in a pen to eat grass, quite a distance away from the arena, but whenever we would approach the side of the arena where we would be heading that way he would speed up, wanting to go see them. I made him walk around the arena a few times until he was only walking, and he finally did it. After a while it gets pretty annoying, having to keep stopping and making him back. I want him to just walk when I tell him to walk and nothing else, and I want him more focused on me. Is there anything I can do to help this?