What Causes Low Blood Sugar Levels?

I have never been diagnosed with Diabetes or Hypoglycemia. That being said however, I feel like something is just not right. So, I did some research, went down and bought a glucometer, and have started keeping a log. Here's my question...No matter when I test my blood sugar, it never rises above 95. Not even right after I eat a big meal. And last night I couldn't sleep, just didn't feel right. Finally got up at 3:00a.m. and ate a small bowl of corn chex, went back to bed, felt very shaky when I got up and showered for work. Tested my blood-sugar at 6:30a.m. and it was 74. Is this normal because I am a 47 yr. old female with no other health problems and I take excellent care of myself. Yet, I always feel fatigued and co-workers say they can actually see the life drain right out of my eyes some days, even though I always eat a healthy breakfast, lunch, dinner, and exercise every day. HELP!