I've never experienced a hypo after an event like that, however when injecting into my stomach area I have hit nerves a few times and even fainted very soon after-and I don't faint easily! If you didn't do any exercise during the day, and you got your nova rapid right then you must have hit a...
I think you should do an increased basal rate at the times you experience highs, but personally when I go to the gym I've found a small snack beforehand and a sports drink throughout works perfectly :)