The general answer to your situation is that you need more insulin. Your challenge is to figure out whether you need more meal insulin for your evening meal or more basal insulin (Lantus) insulin.
I try to eat my last meal of the day relatively early in the evening so that most of the blood glucose/insulin action happens before I go to bed. What time did you eat your evening meal on the two days you write about? What did you eat?
You may test your basal insulin needs by eating the last meal of the day early enough so that five or more hours elapse before you go to bed. Then set your alarm to fingerstick and record your blood sugar values during the night. You may read more about one basal testing protocol at Gary Scheiner’s website.
While you are trying to adjust your insulin dosages it may help you to eat the same meal for a few or even several days in a row. Keep a notebook that can record your blood glucose levels, insulin doses, timing, and any other factor you might think is pertinent. Some people notice better overall blood sugar control is associated with a full night’s sleep.
Be aware that there exists no single perfect insulin dose for you. It will change and the best thing for you to learn is how to adjust when these changes happen. That’s why staging an experiment, like the basal test, is useful.
Good luck! You are asking the right questions.