Hi,
Just a suggestion...do you get up, or go to bed and hence inject your long acting insulin late r on aSunday, but then go back to "normal" weekday times on Monday? I wonder, if you had your Sunday evening basal later in teh evening, but then got up early on Monday and injected again, and then had a your evening does atearlier too, you have justgot too much basal insulin in your system?
Might be way off, not ven sure that you are on basal bolus, but though I would suggest it?