The boundaries of the world expands a little, and your toddler enjoys newfound independence and at the same time afraid of her. Now he plays a toy across the room, and a minute later he was running to you to make sure it is protected.
Perhaps your child is too attached to you at this time, and may be concerned, if you leave it, even if not permanently. Although it is normal for young children to experience strong conflicting emotions. It is important that parents maintain their independence, taking the duality of his emotions (who blame the child for what he wants to be big and small at the same time?) And often hugged him.