Even if your insulin is in date, it can still deteriorate and become less effective at room temp. So changing insulin pens/cartridges/vials is always a good thing to do if you have unexplained highs.
Give your DSN a call for advice today, even if your BS has gone down. If it is stress, it may happen again and it would be good to have advice from her/him about what to do.
There's lots of suggestions here to control highs - things like accurate carb counting, adjusting meal time ratios, correction doses.
Do ask whatever you want