He is irritated. Angry at you and at himself for causing you to get hurt in the process. Optimus could not stand to see you being hurt and damaged. why wouldn’t you just listen?

"I told you to fall back." he scolds, optics scanning you for any more injuries,he sighs, Optimus’s not sure if he enjoys your reckless behavior that much.

He tries not to reveal that he is concerned about you. He doesn't want to be the reason you get injured repeatedly. You're everything to him, his sparkmate.