We all have times like this when your levels just don't behave the way you expect. Could be the end of the honeymoon period.
I've been doing a bit of research around random highs/lows. Apparently, there's a 20% error in the amounts of carbs on food labels, a 20% error in the amount of carbs a diabetic estimates to be in a meal, a 15% error in the reading you get from your BG meter and a 30% error in the amount of injected insulin that enters the bloodstream. So there's a potential of 85% error every time you have a meal. If all, or some of those things go wrong then you get random, confusing readings.
I know you're pretty good with your approach to your diabetes, but for the benefit of others you can reduce these errors by: changing your needle and injection site for each injection, wash your hands before each test, change your lancet before each test, choose an accurate meter rather than one with lots of functionality (I've got the MyLife Pura, supposedly one of the most accurate) and reduce your carb portions.