I tested my blood sugar, 1st night it was 138, next am 112. Is that a concern for a 45 yr old, 20lbs heavy? Should it always be under 100? See a dr?

Needs context. A blood sugar of 138 would be considered high if it were a fasting value. But it would be normal if obtained within two hours of a meal. An am sugar of 112 is slightly high if you are fasting. Talk to your doctor about further testing including fasting and 2 hour post meal testing. You may also benefit from A1c testing which gives the doctor info about average sugar levels over 2-3 months.
See your doctor. Home glucometers are subject to error. How and when blood sugars are tested may also interfere in getting meaningful info. These results must always be verified by lab testing. Best thing to do is see your doctor. Sounds like you merit laboratory testing to determine if you have problems with blood sugar regulation.