Hah! When I started I had the SAME issue! If my guess is right, you're not quite speed vaulting, but you're kinda surpassing a lazy as well.
As I learned later when you clear the obstacle, you push away to maintain momentum, not necessarily to clear the obstacle. Try planting one foot and then pushing away with your hand. Step into the push and boom, you're running again. Trust me, you'll feel the difference.