sounds to me like you need to talk to your doctor about increseing your insulan
"Why would my level be so high?????"
This is difficult to ascertain without knowing your bedtime, morning fasting, preprandial [before meal], and postprandial [2-3 hours after meal] glucose levels. Other questions that will help:
• Are you eating a diabetic diet?
• All you ate was the banana at breakfast?
• Any foods/snacks between breakfast and 3pm?
• Any juices or energy drinks from breakfast to 3pm?
• When and how often do you test?
Start testing to see which foods affect your glucose levels. And, of course, maintain normal body and perform 30-60 mins of daily exercise. If your levels remain high it may be time to see your doctor for adjustments to your medications. Good luck