Fasting numbers


Why are these fasting glucose numbers so hard to control. I’m on 2.5 mg of glyburide at bedtime to try and control them. Some days they are fine and some days they are high. Normally I wake up at around 5:30 every morning during the week and on the weekends I wake up around 8:00. During the week my fasting number is always between 94 and 100. Yesterday when I woke up at 8:00 it was perfect at 87. Today I wake up at 8:00 and it’s 117. I didn’t eat anything different before I went to sleep last night so I just don’t understand why it’s so much higher than it was yesterday morning.