Be kind to yourself. No-one knows how you mark yourself or what your final score is. I never mark myself down for getting the exclamation marks wrong. And I certainly never feel guilty about it! It is not meant to be a strict dictation like in a school exam, and if they read out the punctuation it would certainly disrupt the flow of the passage or the conversation. 

Since it's you grading yourself, why not be a bit more lenient when it comes to punctuation?