It seems like you're experiencing typical disfluencies in speech that everyone gets, rather than stuttering. Mispronouncing words and stumbling over your speech a bit is just part of the human experience - stuttering is chronic disfluencies that impact your speech nearly all of the time. It's likely that you're experiencing these disfluencies because of a change in routine or stress - not sleeping will certainly contribute to it. If it continues for a month or more, I'd consult with a speech language pathologist.