TROUBR, I know what you mean about feeling disappointed when things go pear-shaped and you don't know why. Sometimes I think we can't pinpoint WHY blood sugars act as they do, frustrating as that is. Sarh's point about B.S. rising at certain times of the month is a very valid one. It took me months to suss out why my figures would jump up at certain times, 'cause iwas looking at my food and thinking 'd gone wrong there somewhere. I find my B.S. can be greatly affected by the weather too. If I'm too hot I can go shooting down or shooting up and this also seems to happen if I'm very stressed over something.I have also wondered if the site of injecting can affect B.S. levels. For some odd reason if I inject into my bum, my readings are worse than if I injectinto my stomach.
My best day-to-day readings were shortly after diagnosis and "now" (since cutting down on carbs and portion sizes).
You are probably not to blame for a one-off raised B.S.reading but I so understand you feeling that way.